Ezekiel 12:25 (NIV)
I will fulfill whatever I say.
As time passes and people get older they may begin to doubt the promises God made them when they were young. They may even begin to question the existence of the Almighty. Some may even try to fulfill God's promises by natural means and end up in trouble (ex: Abraham, Sarah, Hagar and Ishmael). We have to understand that God is not slow in fulfilling His promises as the Lord is not bound by time as we mortals comprehend it. Some times it may take 400 years (ex: Israel's deliverance from Egypt) or even 4000 years (ex: the first coming of Christ), but God always fulfills whatever He promised us.