A.T. Robertson Commentary Revelation 1:7

"Behold, he cometh with the clouds; and every eye shall see him, and they that pierced him; and all the tribes of the earth shall mourn over him. Even so, Amen." — Revelation 1:7 (ASV)

Behold, he cometh with the clouds (ιδου ερχετα μετα των νεφελων). Futuristic present middle indicative of ερχομα, a reminiscence of Da 7:13 (Theodotion). "It becomes a common eschatological refrain" (Beckwith) as in Mr 13:26; 14:62; Matthew 24:30; 26:64; Luke 21:27. Compare the manifestation of God in the clouds at Sinai, in the cloudy pillar, the Shekinah, at the transfiguration" (Vincent).

Shall see (οψετα). Future middle of οραω, a reminiscence of Zec 12:10 according to the text of Theodotion (Aquila and Symmachus) rather than the LXX and like that of Mt 24:30 (similar combination of Daniel and Zechariah) and 26:64. This picture of the victorious Christ in his return occurs also in 14:14, 18-20; 19:11-21; 20:7-10.

And they which (κα οιτινες). "And the very ones who," Romans and Jews, all who shared in this act.

Pierced (εξεκεντησαν). First aorist active indicative of εκκεντεω, late compound (Aristotle, Polybius, LXX), from εκ and κεντεω (to stab, to pierce), in N.T., only here and Joh 19:37, in both cases from Zec 12:10, but not the LXX text (apparently proof that John used the original Hebrew or the translation of Theodotion and Aquila).

Shall mourn (κοψοντα). Future middle (direct) of κοπτω, old verb, to cut, "they shall cut themselves," as was common for mourners (Matthew 11:17; Luke 8:52; Luke 23:27). From Zec 12:12. See also Re 18:9.

Tribes (φυλα). Not just the Jewish tribes, but the spiritual Israel of Jews and Gentiles as in 7:4-8. No nation had then accepted Christ as Lord and Saviour, nor has any yet done so.