1. Abraham entertained three strangers (1-8)

After renewing the covenant through circumcision and name-change into Abraham, the Lord appeared to him in the form of three strangers. Abraham was 99 years old. He was resting under the heat of the day. He could have ignored them. Instead, he hurried to meet them. He did not realize who they were at first. He pleaded them not to pass him by. He then like a young man hurriedly ran to Sarah and the servants. He gave a selected tender calf to cook quickly. Heb 13:2 comments that some people entertained the angels without knowing it. How beautiful it is for the whole families to serve strangers with their whole heart as heavenly pilgrims.

2. Sarah will have a son (9-15)

Then the Lord pronounced to give a son to Sarah in a year. But when Sarah overheard it, she laughed to herself. It was because she has passed the age of childbearing. She said, "Will I really have this pleasure after I and my master were worn out and old?" The Lord rebuked her confirming, 'Is anything too hard for the Lord?" No! Nothing is impossible for the Almighty God! Our God is "the God who gives life to the dead and calls into being things that were not" (Romans 4:17).