Lord, Lord - God judges of the heart, not by words, but by works. A good servant never disputes, speaks little, and always follows his work. Such a servant a real Christian is: such is a faithful minister, always intent either on the work of his own salvation, or that of his neighbor; speaking more to God than to men; and to these as in the presence of God. The tongue is fitly compared by one to a pump, which empties the heart, but neither fills nor cleanses it. The love of God is a hidden spring, which supplies the heart continually, and never permits it to be dry or unfruitful. Quesnel.

And why call ye me Lord, Lord,.... Or, "my Lord, my Lord", as the Syriac version renders it; acknowledging, in words, his government over them; claiming an interest in him, and making use of his name and authority:
and do not the things which I say; or "command"; and therefore such words in their mouths would be of no use to them, since they neither did his Father's will, which he taught them, nor observed his commands and ordinances which he enjoined them; and therefore should not enter into the kingdom of heaven, nor be owned by him another day, but should be bid to depart from him; See Gill on Matthew 7:21. See Gill on Matthew 7:22. See Gill on Matthew 7:23.

Why call ye me, Lord, Lord? See notes on Matthew 7:21-27. Luke adds: Digged deep. This is often needful to reach the rock. We must dig deep, even to our heart, to its center, to build upon the Rock, Christ our Lord. The confession of faith in Christ (Matthew 16:16) must be believed with the heart (Romans 10:10), confessed with the mouth, in order that we may be built upon the Rock (Matthew 16:18).

And why call ye me Lord, Lord - What will fair professions avail, without a life answerable thereto? Matthew 7:21.