Subject pronouns I, he, she, it, you, we and they are usually located before the verb to replace a noun, and indicate who performs the action of the verb. In the passage from "Psalm 23," the subject pronoun I refers to the narrator, He refers to God, and thou is an old form of the pronoun you.
I'd say the stressed syllables are "nor mars and nor wars" and non stressed are "his sword and quick fire shall burn" sorry if this is incorrect pls let me know if it was!
