The following is an excerpt from The MacArthur New Testament Commentary on Matthew 7.

Not everyone who says to Me, “Lord, Lord,” will enter the kingdom of heaven; but he who does the will of My Father who is in heaven. Many will say to Me on that day, “Lord, Lord, did we not prophesy in Your name, and in Your name cast out demons, and in Your name perform many miracles?” And then I will declare to them, “I never knew you; depart from Me, you who practice lawlessness.” (Matthew 7:21–23)

A Jew could use the term lord simply as a title of respect and honor, given to any political, military, or religious leader, including teachers. But for those people to say, Lord, Lord, suggests much more than human respect, as their following comments make clear. That they claimed to have prophesied, cast out demons, and performed miracles in Jesus’ name indicates they acknowledged Him as Lord in a supernatural way. Lord was a common Jewish substitute title for Jehovah, or Yahweh, which name they considered too holy to utter. Therefore to address Jesus as Lord was to address Him as the one true God. To address Him as Lord, Lord was to add a spirit of intense zeal to demonstrate strength of devotion and dedication. In verse 22, the three references to your name are emphatic and convey the significance of who He is. Jesus is therefore talking about those who make a profession of faith in Him.

These people claim to be followers of the God of Israel, the Creator and Lord of all earth. Not only that, but they acknowledge Jesus Himself to be divine, because they will say to Me [that is, to Jesus] on that day, “Lord, Lord.” And the fact that they have claimed so many outstanding works in His name tells us they are especially fervent religious workers.

That some of the ones Jesus is talking about here are true believers is shown by His saying, Not everyone and many. The same many who entered the wide gate (v. 13) are now at the end of the broad way facing the Judge. For some people, however, the claim Lord, Lord will be legitimate, because Jesus will have indeed been their Lord on earth and they will have served Him genuinely.

If Jesus is speaking about the great white throne judgment, many professing believers who are not genuine will already have spent centuries in hell awaiting their final judgment (see Luke 16:23–26; Acts 1:25). Because they were so zealous and active and diligent in religious work-in the Lord’s own name-they are incredulous that they are even standing before Christ to be judged. Even at that time they will address Christ as Lord and speak to Him in desperation with the greatest respect and sincerity. Their words and their works will seem impressive to them, but their lives will not support the claim of their lips. In Luke 6:46 Jesus said, “Why do you call Me, ‘Lord, Lord,’ and do not do what I say?”

It is not the one who simply claims the Lord, but the one who does the will of My Father who is in heaven who is saved. The issue is obedience to the Word of God. “If you abide in My Word, then you are truly disciples of Mine,” Jesus said (John 8:31; cf. 6:66–69; Matt. 24:13; Col. 1:22–23; 1 Tim. 4:16; Heb. 3:14; 10:38–39; 1 John 2:19). Salvation and obedience to the will of God are inseparable, as the writer of Hebrews makes clear: “He became to all those who obey Him the source of eternal salvation” (5:9; cf. Rom. 1:5; 6:16; 15:18; 16:19, 26; 1 Pet. 1:2, 22).

Jesus’ word to the disobedient claimers will be, I never knew you; depart from Me, you who practice lawlessness. All their words of respect and honor and all their works of dedication and devotion will be declared empty and worthless. They may have had God’s name in their mouths, but rebellion was in their hearts.