His mercy - Favor shown to the miserable and the guilty.
Is on them - Is shown or manifested to them.
That fear him - That "reverence" or honor Him. One kind of fear is that which a servant has of a cruel master, or which a man has of a precipice, the plague, or death. This is not the "fear" which we ought to have toward God. It is the fear which a dutiful child has of a kind and virtuous father a fear of injuring his feelings; of dishonoring him by our life; of doing anything which he would disapprove. It is on those who have such fear of God that his mercy descends. This is the fear of the Lord which is the beginning of wisdom, Psalm 111:10; Job 28:28.From generation to generation - From one age to another - that is, it is unceasing; it continues and abounds. But it means also more than this. It means that God's mercy will descend on the children and children's children of those that fear him and keep his commandments, Exodus 20:6. In this respect it is an unspeakable privilege to be descended from pious parents; to have been the subject of their prayers, and to have received their blessing. It is also a matter of vast guilt not to copy their example and to walk in their steps. If God is "disposed" to show mercy to thousands of generations, how heavy will be the condemnation if the children of pious parents do not avail themselves of it and early seek his favor!

His mercy is on them that fear him - His exuberant kindness manifests itself in acts of mercy to all those who fear or reverence his name; and this is continued from generation to generation, because he is abundant in goodness, and because he delighteth in mercy. This is a noble, becoming, and just character of the God of the Christians; a being who delights in the salvation and happiness of all his creatures, because his name is mercy, and his nature love.

And his mercy [is] on them (s) that fear him from generation to generation.
(s) To those that live godly and religiously, as the Hebrews say.

And his mercy is on them that fear him,.... Not with slavish fear of hell and damnation, but with reverence and godly fear; with a filial fear, with a reverential love of God, and affection for him; with that fear which springs from the goodness of God, which has that for its object, and is encouraged by it: and though this fear is not the cause and reason of the mercy of God, yet is descriptive of the persons towards whom it is exercised in various ways, and to whom it is openly shown; they hereby appearing to be the vessels of mercy, afore prepared to glory; and in whose redemption, mercy and truth have met together, and who, according to the abundant mercy of God the Father, have been begotten again; whose unrighteousnesses he has been merciful to, and whose sins he will remember no more: and it may have a particular regard to the incarnation of Christ, which in this chapter is said to be in remembrance of mercy; to be the mercy promised, and to come through the tender mercy of our God, Luke 1:54. And which was a mercy Mary considered, not as peculiar to herself, but as extended to all that fear the Lord; not in that age only, but from
generation to generation; to the end of the world, to God's elect in all times and places, who should all be partakers of it, and sharers in it.