Albert Barnes Commentary Psalms 103:4

"Who redeemeth thy life from destruction; Who crowneth thee with lovingkindness and tender mercies;" — Psalms 103:4 (ASV)

Who redeemeth thy life from destruction – That is, who saves it from death when exposed to danger, or when attacked by disease. The word “destruction” or “corruption” here is equivalent to the grave, since it is there that the body returns to corruption. Compare the notes at (Psalms 16:10).

Who crowneth thee – The idea here is not merely that God is the source of these blessings, but that there is something of beauty, of dignity, of honor, as in the conferring of a crown or garland on anyone. Compare the notes at (Psalms 65:11).

With loving-kindness and tender mercies – mercy and compassions. God showed mercy to him – evinced compassion – and these were so abundant that they might be said to be the crown or ornament of his life.