The following is an excerpt from The MacArthur New Testament Commentary on Philippians 1.

For I am confident of this very thing, that He who began a good work in you will perfect it until the day of Christ Jesus. (1:6)

A fourth element of joy is anticipation. Nothing can encourage a Christian so much as the knowledge that, despite life’s uncertainties and difficulties, and no matter how many spiritual defeats there may be long the way, one day he will be made perfect.

Confident translates peitho, which here means to be persuaded of and have confidence in. Paul’s confidence was much more than human hope; it was the absolute confidence that comes from knowing and believing God’s promise that He [God] who began a good work in him will perfect it until the day of Christ Jesus. Salvation is wholly God’s work, and for that reason its completion is as certain as if it were already accomplished.

Began is from enarchomai, a compound verb meaning “to begin in.” It is used only twice in the New Testament, both times in reference to salvation. Paul rebuked certain believers in the Galatian churches who believed that they could finish in their own power what God had divinely begun in their lives solely by the power of His Holy Spirit. “Are you so foolish?” he asked rhetorically. “Having begun by the Spirit, are you now being perfected by the flesh?” (Gal. 3:3). In the present text the apostle, in effect, responds to that same question, assuring the Philippians that their salvation is solely a gracious work of God. God requires faith for salvation, but faith is not a meritorious work. Salvation is by the power of God in response to faith; and, as already noted, faith itself is God’s work, divinely initiated and divinely accomplished (Eph. 2:8–9). Although Lydia, the first convert in what would become the church at Philippi, believed the gospel of Christ, Luke made it clear that “the Lord opened her heart to respond to the things spoken by Paul” (Acts 16:14).

Later in the present epistle, Paul emphasized that “to you it has been granted for Christ’s sake, not only to believe in Him, but also to suffer for His sake,” and “it is God who is at work in you, both to will and to work for His good pleasure” (Phil. 1:29; 2:13). “As many as received Him [Christ],” John declared, “to them He gave the right to become children of God, even to those who believe in His name” (John 1:12). When “the apostles and the brethren who were throughout Judea heard that the Gentiles also had received the word of God” through the witness of Peter, “those who were circumcised took issue with him,” believing that the gospel was only for Jews or Jewish converts. But after they heard Peter’s report, “they quieted down and glorified God, saying, ‘Well then, God has granted to the Gentiles also the repentance that leads to life’ ” (Acts 11:1–2, 18). “In the exercise of His will,” James wrote, “He brought us forth by the word of truth, so that we would be a kind of first fruits among His creatures” (James 1:18).

As noted earlier, salvation is solely by God’s grace. God “chose us in Him before the foundation of the world, that we would be holy and blameless before Him” (Eph. 1:4). God chose all believers before time, long before they could possibly choose Him; and apart from His choice of them, they could not choose Him (John 6:44). It has always been true, in every age and circumstance, that only “as many as had been appointed to eternal life [have] believed” (Acts 13:48). Paul clearly expressed that truth in Romans 5:8–10:

God demonstrates His own love toward us, in that while we were yet sinners, Christ died for us. Much more then, having now been justified by His blood, we shall be saved from the wrath of God through Him. For if while we were enemies we were reconciled to God through the death of His Son, much more, having been reconciled, we shall be saved by His life.

Later in that epistle Paul gave a parallel to Philippians 1:6, noting that “those whom [God] foreknew, He also predestined to become conformed to the image of His Son, so that He would be the firstborn among many brethren; and these whom He predestined, He also called; and these whom He called, He also justified; and these whom He justified, He also glorified” (Rom. 8:29–30). All the chosen will be glorified. God will finish what He has begun.

Every aspect of salvation is by God’s sovereign will and choice. Paul wrote to the Ephesians that:

God, being rich in mercy, because of His great love with which He loved us, even when we were dead in our transgressions, made us alive together with Christ (by grace you have been saved), and raised us up with Him, and seated us with Him in the heavenly places in Christ Jesus, so that in the ages to come He might show the surpassing riches of His grace in kindness toward us in Christ Jesus. For by grace you have been saved through faith; and that not of yourselves, it is the gift of God. (Eph. 2:4–8; cf. Titus 3:4–6; James 1:18; 1 Peter 1:2–3)

It is the Lord who begins the work of salvation, and it is the Lord, through His Holy Spirit, who will perfect it. To the Galatians Paul wrote, “I have been crucified with Christ; and it is no longer I who live, but Christ lives in me; and the life which I now live in the flesh I live by faith in the Son of God, who loved me and gave Himself up for me” (Gal. 2:20). Epiteleo (to perfect) is a compound, formed by the preposition epi and the verb teleo (“to complete”) to give the intensified meaning of “fully completed.” Paul was absolutely certain that God will fully complete His work of salvation in the Philippians. There is no possibility of failure or of partial fulfillment.

The eschatological expression the day of Christ Jesus does not refer to what both the Old and New Testaments prophesy as the final Day of the Lord, the time of God’s judgment on the sinful world. The Day of the Lord is described by Paul in 1 Thessalonians:

For you yourselves know full well that the day of the Lord will come just like a thief in the night. While they are saying, “Peace and safety!” then destruction will come upon them suddenly like labor pains upon a woman with child, and they will not escape. But you, brethren, are not in darkness, that the day would overtake you like a thief. (5:2–4; for more information on the Day of the Lord, see Isa. 13:6–22; Joel 1:15; 2:11; Acts 2:20; 2 Thess. 1:10, “that day”; 2 Peter 3:10, and Revelation 1–11, The MacArthur New Testament Commentary [Chicago: Moody, 1999], 199–201)

Also an eschatological expression, the day of Christ Jesus, on the other hand, clearly refers to the time when believers will be glorified, when their salvation will be completed and made perfect (1 Cor. 3:10–15; 2 Cor. 5:10). It is the same as “the day of Christ” that Paul mentions several times later in Philippians, the day for which Christians should be prepared by living sincerely and blamelessly (1:10) and by “holding fast the word of life” (2:16). In his first letter to the Corinthian church, the apostle called it “the day of our Lord Jesus Christ” (1 Cor. 1:8), and in his second letter to them he called it “the day of our Lord Jesus” (2 Cor. 1:14). In each instance, the personal names Jesus or Christ are given (rather than Lord), and in each instance the reference is to the time when believers will fully share the Lord’s perfect righteousness, when “Christ is formed in [them]” (Gal. 4:19), and “[they] also will be revealed with Him in glory” (Col. 3:4).

Believers are “predestined to become conformed to the image of [God’s] Son” (Rom. 8:29), because “just as [they] have borne the image of the earthy, [they] will also bear the image of the heavenly, … [and] in a moment, in the twinkling of an eye, … [they] will be changed.… For this perishable must put on the imperishable, and this mortal must put on immortality” (1 Cor. 15:49, 52–53). “We know that when [Christ] appears,” John wrote, “we will be like Him, because we will see Him just as He is” (1 John 3:2). Peter wrote: “When the Chief Shepherd appears, [we] will receive the unfading crown of glory” (1 Peter 5:4). Although a believer living in unrepentant sin may be delivered temporarily to Satan for discipline, “his spirit [will] be saved in the day of the Lord Jesus” (1 Cor. 5:5). The day of Christ Jesus is the time of perfection and glorification, when the glorious manifestation of the children of God will finally come (Rom. 8:18–19, 23).

When God saves, He saves completely and eternally. In promissory covenant terms, to be justified is to be sanctified and glorified. There is no such thing as experiencing one of those aspects of salvation without the other two. Each is an integral and necessary part of the whole continuum of salvation. For God to begin salvation in a person’s life is an irrevocable guarantee of His completing it. As William Hendriksen has observed, “God … is not like men. Men conduct experiments, but God carries out a plan. God never does anything by halves” (Philippians, 55).

The Lord said of David: “I will not break off My lovingkindness from him, nor deal falsely in My faithfulness” (Ps. 89:33; cf. v. 20). Jesus gives every believer the absolute promise that “all that the Father gives Me will come to Me, and the one who comes to Me I will certainly not cast out.… This is the will of Him who sent Me, that of all that He has given Me I lose nothing, but raise it up on the last day” (John 6:37, 39). Later He reiterated that promise, saying, “My sheep hear My voice, and I know them, and they follow Me; and I give eternal life to them, and they will never perish; and no one will snatch them out of My hand” (John 10:27–28). Paul declared, “I am convinced that neither death, nor life, nor angels, nor principalities, nor things present, nor things to come, nor powers, nor height, nor depth, nor any other created thing, will be able to separate us from the love of God, which is in Christ Jesus our Lord” (Rom. 8:38–39). The apostle wrote to Timothy that “the firm foundation of God stands, having this seal, ‘The Lord knows those who are His’ ” (2 Tim. 2:19; cf. John 10:14). Peter exulted:

Blessed be the God and Father of our Lord Jesus Christ, who according to His great mercy has caused us to be born again to a living hope through the resurrection of Jesus Christ from the dead, to obtain an inheritance which is imperishable and undefiled and will not fade away, reserved in heaven for you, who are protected by the power of God through faith for a salvation ready to be revealed in the last time. (1 Peter 1:3–5; cf. Jude 24)

It is easy for believers to become discouraged when they focus on their problems and imperfections (and those of other believers). Those sins should not be ignored or minimized; but neither should they be allowed to overshadow the marvelous reality of the future perfection of the church and of every individual believer, as God’s Word guarantees so frequently and clearly. Remembering that glorious truth removes the debilitating pressure of doubt and fosters triumphant joy, gratitude, and anticipation. In so doing, it also frees God’s people to live more abundantly and fruitfully.

The nineteenth-century commentator F. B. Meyer wrote,

We go into the artist’s studio and find there unfinished pictures covering large canvases, and suggesting great designs, but which have been left, either because the genius was not competent to complete the work, or because paralysis laid the hand low in death; but as we go into God’s great workshop we find nothing that bears the mark of haste or insufficiency of power to finish, and we are sure that the work which His grace has begun, the arm of His strength will complete. (The Epistle to the Philippians [Grand Rapids: Baker, 1952], 28)

God has no unfinished works. The God who saves is the God who justifies, sanctifies, and glorifies. The God who begins is the God who completes. During His incarnation, the Lord gave this absolute and unambiguous assurance, which is a source of joy to all those who will ever trust in Him: “All that the Father gives Me will come to Me, and the one who comes to Me I will certainly not cast out” (John 6:37).