The following is an excerpt from The MacArthur New Testament Commentary on Luke 6.

Why do you call Me, "Lord, Lord," and do not do what I say? (Luke 6:46)

Jesus closed His sermon by challenging His hearers to make a choice. People face decisions throughout their lives, choices about diet, medical care, lifestyle, career, relationships, and education, to name a few. But the one that far overshadows all the rest is the choice that fixes a person’s eternal destiny. The concluding parable of the Sermon on the Mount reveals two aspects of that decision:  its nature and its consequences.

Religion thrives in the world because people want to go live after death in heaven, however they define it. Whether conceived of as the nirvana of Buddhism, the paradise of Islam, the eternal progression to godhood of Mormonism, or the freedom from the cycle of reincarnation and union with Brahman of Hinduism, religions offer some form of bliss, happiness, fulfillment, or reward on a higher plane after this life.

In this age of tolerance and rejection of absolute truth (especially religious truth) there is a widespread belief that anyone who is sincere in their faith will go to heaven. Even many professing evangelicals hold to an inclusive view of the gospel. God, they maintain, will accept those who are sincere in their religious commitment, even if they never leave their false religions, or profess faith in Jesus Christ. In fact, some even argue that they may actually be aided in coming to God by those false religions.

But the gospel is uncompromisingly exclusive. Jesus declared, "I am the way, and the truth, and the life; no one comes to the Father but through Me" (John 14:6). The early Christians proclaimed the truth that "there is salvation in no one else [other than Jesus Christ]; for there is no other name under heaven that has been given among men by which we must be saved" (Acts 4:12).

If there were any religion apart from biblical Christianity close enough to the truth that its followers might get to heaven it would be Judaism. After all, Christians and Jews have much in common. Both believe in the God of Abraham, Isaac, and Jacob. Both believe that God is holy, sovereign, omniscient, omnipresent, immutable, creator, sustainer, and judge. Both believe in the reality of sin and the need for righteousness. Both believe in virtues such as humility; honesty; kindness, and forgiveness. And Jews believe in the Old Testament Scriptures.

But it was to people who held those very beliefs that Jesus addressed this sermon. Many were fascinated by Him, as evidenced by the huge crowds that followed Him wherever He went. Some even identified themselves as His disciples and affirmed Him to be in some sense their master or teacher. Yet despite all of that, many fell short of salvation because, as the Lord's pointed question "Why do you call Me, 'Lord, Lord,' and do not do what I say?" makes clear, they failed to obey Him.