'Act' in the Bible

Stay the night, and if he fulfills his duty as your related redeemer in the morning, that will be acceptable. But if he isn't inclined to do so, then, as the LORD lives, I will act as your related redeemer myself. So lie down until morning."

So I thought to myself I ought to tell you that you must make a public purchase of this before the town residents and the elders of my people. So if you intend to act as the related redeemer, then do so. But if not, let me know, because except for you and I after you there is no one to fulfill the duties of a related redeemer." The man responded, "I will act as related redeemer."

At this, the nearer related redeemer replied, "Then I am unable to act as related redeemer, because that would complicate my own inheritance. You act instead as the related redeemer, because I cannot do so."