In algebra, x represents the unknown—the variable that, once you solve for it, makes everything else make sense. Abraham’s life looks that way too: unlikely candidate, impossible promise, uncertain path. But Genesis 15 reveals the x—the one variable that explains everything. It was faith in God. This chapter, which many scholars consider the most important in the entire Old Testament, reveals for the first time how a sinful human being can be made right with a holy God. Abraham shows us that faith isn’t passive; it drives out fear, it takes God at His word, and it holds on to His promises. There are three things Abraham did that activated the God factor in his life, and they’ll do the same in yours.