Consider Abraham and Sarah again. God waited twenty-five years before He fulfilled the promise that He gave to them. If we would care to look, you could go back to Romans 4:19 and Hebrews 11:11. Both of those verses confirm each other. God purposely waited until neither Abraham nor Sarah were capable of producing a child. They exhibited faith during the 25 years, but God manipulated circumstances so that Abraham and Sarah, regardless of their great faith, regardless of their belief, regardless of how they acted upon what they believed, they would know that God worked a miracle. God gave them grace in order to fulfill His own promise to them.
Abraham and Sarah had to do what they did, but that still did not fulfill God's Word. It was only a response God expected them to do. Now they are examples that are held up to us because they did do the right thing, but you see this sets a pattern, that as we go through life, God expects us to exercise faith, and there are times that He is going to bring us to our own personal Red Seas, that even though He brings us to the Red Sea, we have to understand that He is the one that parts the water.
If we wanted to follow Abraham and Sarah, would we not see that they had their problems? They failed along the way. God only shows us a couple of them. They might have failed ten or fifteen times more times than God showed us during that twenty-five years. They never forgot their basic responsibility to God. Sarah tried to get Abraham a child through Hagar. That was not the right thing to do. Abraham went along with it. That was not the right thing to do. It was not an act of faith.
You see we can learn from this. God is going to take us to where we understand that we are saved in spite of our weaknesses and that salvation comes by grace. But He still expects us to exhibit faith. Because if we do, then there is going to be steady growth. Not that we will never fail, but there is going to be steady growth from the time of our conception to the time of our birth into His family. So, we will fail tests along the way, but He patiently keeps on working with us. It is not the end of the story, and on we go.
See where faith comes from? It does not happen by magic.