The New John Gill Exposition of the Entire BiblePsalms 118:20
This gate of the Lord, into which the righteous shall enter.
This seems to be spoken by some other person or persons, distinct from
David and the Messiah, pointing at some particular and principal gate,
upon hearing the above word: by which is meant, not the gate of the
house of the sanctuary of the Lord, as the Targum; but the Messiah
himself, afterwards spoken of as the stone rejected by the builders,
and made the head of the corner; who is the way of access to God; the
door into the church or sheepfold; the strait gate that leads to
eternal life; by which none but righteous persons enter into heaven;
even such who are made righteous, through the imputation of his
righteousness to them; see (John 10:1,9) (14:4) (Matthew 7:14) .