A.T. Robertson Commentary Revelation 11:19

"And there was opened the temple of God that is in heaven; and there was seen in his temple the ark of his covenant; and there followed lightnings, and voices, and thunders, and an earthquake, and great hail." — Revelation 11:19 (ASV)

Was opened (ηνοιγη). Second aorist passive indicative of ανοιγω, with augment on the preposition as in 15:5. For the sanctuary (ναος) of God in heaven see 3:12; 7:15; 15:5ff.;21:22.

Was seen (ωφθη). First aorist passive indicative of οραω.

The ark of his covenant (η κιβωτος της διαθηκης αυτου). The sacred ark within the second veil of the tabernacle (Hebrews 9:4) and in the inner chamber of Solomon's temple (1 Kings 8:6) which probably perished when Nebuchadrezzar burnt the temple (2 Kings 25:9; Jeremiah 3:16). For the symbols of majesty and power in nature here see also 6:12; 8:5; 11:13; 16:18,21.