Why did God decide hypocrisy for some people?

Verses 1-3 of Chapter 63
When the hypocrites come to you, they say: "We bear witness that you are indeed the Messenger of Allah.'' Allah knows that you are indeed His Messenger, and Allah bears witness that the hypocrites are liars indeed. They have made their oaths a screen. Thus they hinder (others) from the path of Allah. Verily, evil is what they used to do. That is because they believed, and then disbelieved; therefore their hearts are sealed, so they understand not.