When God makes a promise, it is as good as done. But, we may have to wait for it, which of course is challenging at times. Most people do not like to wait. Waiting can be frustrating, annoying, aggravating--even in simple matters, like waiting in line at a store or sitting in traffic. However, waiting can also be gratifying, especially when the promise comes!
Abraham, who is mentioned in Hebrews 6, had to wait for the promise of Isaac. In his wait, he and his wife, Sarah, took matters into their own hands. They had a son, Ishmael, through Sarah's handmaid, Hagar (Genesis16). But, this was not the son of promise (Genesis 15).
It's important to not take matters into our own hands and attempt to "be like God". We will make a mess every time! If God has promised you something, and you are in a season of waiting, remember that he cannot lie!
As you wait, continue to pray,have faith, trust, hope and believe that God will do what he has promised. Meditate on the scriptures that align with what God has promised. He will bring it to pass!