"Let us have a covenant with each other ... with my father and your father" or "Let us make a peace treaty ... with my father and your father". Asa asked the king of Aram to help him instead of trusting God to help him. This was sinful because he disobeyed Yahweh.
"Do not be loyal to Baasha king of Israel as you promised in your covenant with him" or "Break your covenant with Baasha, king of Israel, and attack Israel". Asa wanted Ben Hadad to attack Israel. Ben Hadad could only do that if he broke his covenant.