Avram's Faith and the Promise of the Stars

Hashem told Avram that his children would be like the stars above, unable to be counted. Avram trusted in this promise and it was considered an act of righteousness.

Why was it an act of righteousness? Either he believed the promise or he didn’t. It wasn’t an act. Secondly, what is the deal with the stars being impossible to count?

The reason one can’t count the stars is not merely because there are so many of them. It’s impossible because they are not all visible to the eye. Similarly, when Hashem made Avram the promise that he would have children, even though he was already past the age when most people had them, he made a conscious decision to believe it, knowing that there are some things we can’t see.