Sarah's faith began in unbelief but it ended with her experiencing what was humanly impossible, i.e. God's possible, when after 25 years of waiting she gave birth to the promised son, Isaac. There are many lessons we can learn from Sarah about faith. One of the most important is that faith must be personal. Abraham had great faith, but Sarah needed her own faith. This principle is true for us. We may have people in our lives who have great faith but their faith won't substitute for our faith. Another lesson to learn is that often when we have to wait in faith we end up seeing our faith grow to new levels.