'Pledges' in the Bible

Most certainly [Lord] You have abandoned your people, the house of Jacob,Because they are filled with influences from the east,And they are soothsayers [who foretell] like the Philistines;Also they strike bargains with the children of foreigners (pagans).

So now, exchange pledges with my master the king of Assyria and I will give you two thousand horses, if you are able on your part to put riders on them.