Luke 10:20

μὴ χαίρετε … χαίρετε δὲ ὅτι. Here, as often, the ‘not’ followed by ‘but’ means ‘not so much … as that.’ “Nolite tam propterea laetari … quam potius.” This idiom, which is very important to observe in the interpretation of Scripture, is found in Acts 5:4 (not so much to man, as to God), 1 Corinthians 15:10 (not I alone, but the grace of God with me), &c. See Winer, p. 621.

ἐνγέγραπται ἐν τοῖς οὐρανοῖς. ‘Have been recorded in the heavens’. On this ‘Book of God,’ or ‘Book of Life,’ see Exodus 32:32; Psalms 69:28; Daniel 12:1; Philippians 4:3; Hebrews 12:23; Revelation 13:8; Revelation 20:12; Revelation 21:27. Such a record is the opposite to being “written in the earth,” Jeremiah 17:13. The reading ἐγράφη would point to the single fact of their names being inscribed; ἐγγέγραπται, to their standing permanently recorded. Comp. Esther 10:2.