The context of Matt. 7:21-23 near the end of the Sermon of the Mount is found in the rest of the Sermon on the Mount.
If they say “Lord, Lord,” but remain on the popular broad way of 7:13-14, they are not saved. But if they stay on the harder way by faith in spite of their trials and tribulation, they are truly living out the “Lord, Lord, help me” life.
If they show false fruit, like the false prophets of 7:15-20, they are not living as though Christ is “Lord,” but their appetites are.
If they are not confessing their sins as in the Our Father prayer of 6:9-15, then they are not being forgiven by the Father. They are not recognizing their sinful life and crying out “Lord, Lord, deliver me.”
If they are fasting and making a big show of it, showing that their spiritual life does not consist of happily abiding in Christ secretly, as in 6:16-18, then “Lord, Lord” is not real to them.
If they do not murder but hate people in their hearts, 5:21-22; if they do not commit adultery but lust after others as in 5:27-28; then they have not been transformed by the Spirit leading them to repentance, which will happen with those who desire deliverance via “Lord, Lord, help, help!”
If they are not doing the will of Jesus after reading the Sermon, 7:24-25, then their lives will reveal it with its trials, since calling on the Lord indicates deep trust through the trials. “Lord” is not a mere title, but a holy elevation of superiority and authority over us in every way. He who hears Christ’s words and follows them, 7:26-27, will find their house remaining firm in trials.
These thoughts came from The Divine Conspiracy by Dallas Willard, which includes an inspiring exegesis of the entire Sermon on the Mount.
