We are prone to undervalue promises because of how they are flippantly used in our culture. However, God's promises are rooted in his unchanging character. Promises, by definition, have a waiting period before they are fulfilled and waiting is a big part of what it means to follow Jesus. In Hebrews, Abraham is given as an example of someone who believed God's promise in spite of circumstances that suggested otherwise. The ultimate fulfillment of God's promise to Abraham was Jesus.