Psalms 103:11

For as the heaven is high above the earth, [so] great is his mercy toward them that fear him.

Ver. 11. For as the heaven is high above the earth] How high the third heaven is cannot be conjectured. But for the middlemost heaven (wherein the sun, moon, and stars are placed), how exceeding high it is may be guessed and gathered, in that the stars (whereof those of the first magnitude are said to be every one above a hundred and seven times as big again as the whole earth) do yet seem to us but as so many sparks or spangles. See Pro 25:3 Ephesians 4:10 .

So great is his mercy] The heavens are exceeding high above the earth, but God's mercy to his is above the heavens, Psalms 108:4. The original word, gabbar, here used, is the same with that, Genesis 7:20, used for the prevailing of the waters above the mountains.