Albert Barnes Commentary Psalms 102:19

"For he hath looked down from the height of his sanctuary; From heaven did Jehovah behold the earth;" — Psalms 102:19 (ASV)

For he hath looked down from the height of his sanctuary - From his high and holy dwelling-place, in heaven. The word here rendered “looked down,” means, in Kal, to lay upon or over; then, in Niphil, to lie out over anything, to project; and then, to bend forward. It then means to bend or incline forward with an intention to look at anything, as from a window, Genesis 26:8. Compare Psalm 14:2. See also Psalm 85:12, note; 1 Peter 1:12, note.

From heaven did the Lord behold the earth - Did he look abroad over all the world.