David is speaking to himself, so he uses the words "your" and "you" to refer to himself. Many translations express this with "my" and "me," as the UDB does.
Here the words "your life" are a metonym for the person. The words "redeems ... from the pit" here are a metaphor that speaks of Yahweh saving the writer from certain death as if the writer were already dead and Yahweh had paid the one who keeps the dead in a pit so that the writer could come back to life. Alternate translation: "He saves me from dying" (See: [[rc://en/ta/man/jit/figs-metaphor]])
Here blessing someone and treating them with great honor is described as if it were placing a crown on that person's head. The abstract nouns "faithfulness" and "mercy" can be translated with adverbs. Alternate translation: "he blesses you by acting faithfully and mercifully towards you" (See: [[rc://en/ta/man/jit/figs-metaphor]] and [[rc://en/ta/man/jit/figs-abstractnouns]])