en_tn/1sa/25/31.md

my master ... my master ... my master ... your servant

Abigail speaks of herself and David as if they are two different people to show that she respects David. "you ... you ... you ... me" (See: rc://en/ta/man/translate/figs-pronouns)

This will not be a staggering burden for you

Abigail is stating that if David chooses not to take revenge he will have a clear conscience when Yahweh makes him king of Israel. This can be stated in positive form. Alternate translation: "You will always be glad you acted as you did" (See: rc://en/ta/man/translate/figs-litotes)

when Yahweh will do good for my master

That is, when Yahweh actually makes him king after Saul's reign is over.