A.T. Robertson Commentary Revelation 7:11

"And all the angels were standing round about the throne, and [about] the elders and the four living creatures; and they fell before the throne on their faces, and worshipped God," — Revelation 7:11 (ASV)

Were standing (ιστηκεισαν). Past perfect active of ιστημ intransitive and used like an imperfect as in Joh 19:25.

Round about (κυκλω). Preposition (in a circle) with genitive as in 4:6; 5:11. The angels here rejoice in the salvation of men (Luke 15:7,10; 1 Peter 1:12).

Upon their faces (επ τα προσωπα αυτων). In reverential worship of God as in 11:16. For this worship (fell and worshipped) see also 4:10; 5:14; 11:16; 19:4,10; 22:8. The dative τω θεω (God) with προσκυνεω (to worship) is the usual construction for that meaning. When it means merely to do homage the accusative case is usual in this book (Charles). But in the Fourth Gospel the reverse order is true as to the cases with προσκυνεω (Abbott, Joh. Vocab. pp. 138-142).