The name Isaac—'laughter'—suggests his optimistic disposition, someone not afflicted by fear and doubt. Isaac serves as a type of Christ, honoring his father.
Just as the child of the flesh persecuted the child of promise, the spiritual children of God can expect persecution from those living according to the flesh.
Based on his long friendship with God, Abraham could systematically calculate the reliability of God's promises even in the lack of visual evidence.
Abraham, the father of the faithful, did not have a blind faith; it was based upon observation of God's proven track record of faithfulness.
Abraham is the only biblical character singled out as a type of God the Father. He is also the only one to be called 'friend of God,' and is a good model.
If we hold fast to principles, though it may seem initially uncomfortable and fearful, we will eventually receive respect and even admiration.
Abraham's experiences teach us not to try to force God's will. When any sin or self-will is involved, the fruits of such an endeavor will be bitter.
We earn God's favor by obedience; there is a direct tie between submission to His will and His favor. The more one submits, the more favor and grace accrues.