Psalm 103:11 (ESV) … “For as high as the heavens are above the earth, so great is his steadfast love toward those who fear him;”
Boundless in extent towards his chosen is the mercy of the Lord; it is no more to be measured than the height of heaven or the heaven of heavens. “Like the height of the heaven” is the original language, which implies other points of comparison besides extent, and suggests sublimity, grandeur, and glory.
As the lofty heavens canopy the earth, water it with dews and rains, enlighten it with sun, moon, and stars, and look down upon it with unceasing watchfulness, even so the Lord’s mercy from above covers all his chosen, enriches them, embraces them, and stands for ever as their dwelling-place. The idea of our version is a very noble one, for who shall tell how exceeding great is the height of heaven? Who can reach the first of the fixed stars, and who can measure the utmost bounds of the starry universe? Yet so great is his mercy!
Oh, that great little word so! All this mercy is for “them that fear him;” there must be a humble, hearty reverence of his authority, or we cannot taste of his grace. Godly fear is one of the first products of the divine life in us, it is the beginning of wisdom, yet it fully ensures to its possessor all the benefits of divine mercy, and is, indeed, here and elsewhere, employed to set forth the whole of true religion.
Many a true child of God is full of filial fear, and yet at the same time stands trembling as to his acceptance with God; this trembling is groundless, but it is infinitely to be preferred to that baseborn presumption, which incites men to boast of their adoption and consequent security, when all the while they are in the gall of bitterness. Those who are presuming upon the infinite extent of divine mercy, should here be led to consider that although it is wide as the horizon and high as the stars, yet it is only meant for them that fear the Lord, and as for obstinate rebels, they shall have justice without mercy measured out to them.[1]
[1] Spurgeon, C. H. (n.d.). The treasury of David: Psalms 88-110 (Vol. 4, p. 280). London; Edinburgh; New York: Marshall Brothers.