en_tn/1sa/25/30.md

Abigail continues to reason with David.

this matter will be no sorrow to you

Abigail is stating that if David chooses to refrain from taking revenge he will have a clear conscience when Yahweh makes him king of Israel.

the good things which he has promised you

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