From the account of Isaac's birth there are many important lessons we should learn. Five are extremely significant.
First, God is in no hurry to work out His plans. He is never too late; He is always on time. Man frets and worries and is always in a hurry to work out his plans.
Second, God is almighty. Nothing can hinder or thwart the outworking of God's purpose. Abraham was old and Sarah was barren, but these obstacles presented no difficulty to God.
Third, God is faithful. He promised Sarah a son. From the standpoint of human reasoning, it seemed like a foolish promise. However, the promise of God was sure because He is always faithful in keeping His promises.
Because God's word is absolutely sure, in times of doubt and discouragement we need to come to the Word of God to check our spiritual lives and to remind ourselves of His faithfulness.
Although we may not be able to understand how God can fulfill His promises to us, our attitude should be: If God says it, that settles it.
Fourth, faith is tested so it might be proven to be genuine. A faith that cannot endure trial is really no faith at all.
Fifth, God has a set time for everything. It is important that we learn this lesson well. God has an appointed time for accomplishing His will. Nothing is left to chance.