The cost of idolatry, giving tithes and other rules: Deuteronomy 13–16:17
Imagine this: a prophet turns up and promises miracles AND delivers. Who wouldn’t believe he’s from God?
But what if that same prophet starts leading people away from God? Don’t listen to him (or her):
Deuteronomy 13:1–3 Suppose there are prophets among you or those who dream dreams about the future, and they promise you signs or miracles, and the predicted signs or miracles occur. If they then say, ‘Come, let us worship other gods’—gods you have not known before—do not listen to them.
In fact, you should remove any chance of their doing it again, by putting them to death (see 13:5).
Jesus later said that miracles (signs and wonders) could and will be used in an effort to deceive the elect (see Matthew 24:24). He told us to:
Matthew 7:15 Watch out for false prophets. They come to you in sheep’s clothing, but inwardly they are ferocious wolves.
Just doing miracles, even in His name, wouldn’t be enough. It is relationship with Him that counts.
Matthew 7:21–23 Not everyone who says to me, ‘Lord, Lord,’ will enter the kingdom of heaven, but only the one who does the will of my Father who is in heaven. Many will say to me on that day, ‘Lord, Lord, did we not prophesy in your name and in your name drive out demons and in your name perform many miracles?’ Then I will tell them plainly, ‘I never knew you. Away from me, you evildoers!’