Charles H. Spurgeon on Psalms 108:4

The mercy of God was then great above the heavens, when the God man, Christ Jesus, was raised to the highest heavens, and the truth of our salvation established on the very throne of God. —W. Wilson.

Verses 4-5. There is more stuff and substance of good in the Lord's promises than the sharpest sighted saint did or can perceive; for when we have followed the promise, to find out all the truth which is in it, we meet with a cloud of unsearchable riches, and are forced to leave it there; for so much is included in this, Thy truth reacheth unto the clouds. The height of our praising of God is to put the work of praising God upon himself, and to point him out unto others as going about the magnifying of his own name, and to be glad for it, as here; Be thou exalted, O God, above the heavens; and thy glory above all the earth. —David Dickson.

Verses 4-6. There is great confidence here, and, as ever, mercy to the soul which knows itself and comes before truth. But, then, for its own deliverance and blessing it looks to the exalting of God. This shows it must be a holy, righteous exalting. "Be thou exalted, O God, above the heavens: and thy glory above all the earth; that thy beloved may be delivered." It is a blessed thought, and this is what faith has to lay hold of now, even in the time of trial, that our blessing and God's glory are one, only we must put his glory first. —J.N. Darby.