Charles Ellicott Commentary Psalms 89:7

"A God very terrible in the council of the holy ones, And to be feared above all them that are round about him?" — Psalms 89:7 (ASV)

It is better to take this verse in apposition with the foregoing: God sublime in the council of the holy ones,
And terrible among those surrounding him.

For a picture of the court of heaven see Job 1:6.