The Lord first made a covenant agreement with Abraham while he was living in Ur of the Chaldeans,12:2-3. The covenant was repeated on a number of occasions and was reaffirmed to Abraham's descendants. In short, it involved a promise of a land, a people and a blessing to the world. When Abraham was ninety-nine years old and living in Canaan with his wife Sarah, the Lord promised them a boy child, 17:15-21. The impression is that Abraham believes the promise, even though they are both too old, although Sarah doesn't. While camped at Mamre, Abraham "entertained angels without knowing it", and they reaffirm the promise, most likely for Sarah's benefit. They jog her little faith with the question, "Is anything too hard for the Lord?"
v1-2a. Mamre, some 5km North of Hebron, was an ancient Palestinian forest and religious site. Abraham spent some time there, although there is no evidence he was involved in the local pagan worship, since he built his own alter to worship the one true God. The Lord revealed himself to Abraham in the visit of three travelers. They were most likely angels, although some commentators say they were the Father, Son and Holy Spirit, while others say it was Jesus (the Lord) in the company of two angels.
v2b. The visitors arrive at siesta time, but Abraham is quickly to his feet and fervently welcomes them, bowing before them. This is typical of Bedouin hospitality, although Abraham may sense they are not ordinary travelers.
v3-8. Abraham's hospitality continues in line with Near Eastern tradition. He invites them to stay and addresses them with respect, "lord". He addresses himself as their "servant" and happily serves them, bringing water to wash their feet and arranging food for them, setting it before them and standing by as if their servant.
v9-12. The visitors get to the point of their visit, namely, Sarah and her little faith. In her hearing they restate the promise, "Sarah your wife will have a son." She laughs to herself, for she knows she is well beyond childbirth and Abraham well past servicing her; "will I now have this pleasure?"
v13-15. The visitors pick up on her doubts and remind her that nothing is too hard for the Lord, cf. Jer.32:17ff, 27ff, Zech.8:6. They restate the promise, "next year... Sarah will have a son." Sarah is taken back by this and tries to deny that she laughed at their prediction.
"With God all things are possible", Matt.19:26.
In my last parish a member told me of the dark years she spent caring for her husband as he slowly died from cancer. I knew exactly how she felt, for my own son went through a similar slow death. There is lots of pain in such a loss. Anyway, he started going to healing services and was convinced that he would be healed. As he deteriorated, some of his prayer-partners approached his wife and told her that the problem was her's. She doubted, as Sarah doubted, and because of her faltering faith, her husband was dying. Their intentions were good, but their actions were evil. She was destroyed, and now, not only did she have to deal with the loss of her husband, she had to deal with her own sense of guilt, as if the fault was her's.
It is clear from the scriptures that faith is an essential element in our approach to God. The problem we face is to know what faith entails. I remember my own confusion as a young person. To my mind, faith was a doubt-free reliance on God. As I could never achieve such a perfect state, I was left in limbo.
Faith is reliance, stickability, dependence, firmness.... in God's Word, his promises, his covenant agreement with us. Faith is a reliance on the notion that what God promises, he will do, because nothing "is too hard for the Lord." It is quite a false notion to believe that God will do what we want him to do as long as we can conjure up a form of doubt-free faith. Faith is a reliance, not on our own desires, needful or otherwise, but rather on the promises of God. Nor must our faith in the Lord's Word be doubt-free. Faith as small as a mustard seed can move the mountain. Our reliance on the promise may well be filled with doubt, but reliance is what is important, not doubts. Initially Abraham believed and finally Sarah believed, Heb.11:11. They relied on the promise, with all their many questions, doubts and fears.
Abraham and Sarah's faith was repeated by the remnant people of Israel all the way through to the disciples of Jesus. Mary knew to sit at Jesus' feet to hear his words of life. We, the true descendants of Abraham and Sarah, the body of Christ, do well when we rest on the promises in God's Word as they did.
Consider the meaning of the word "faith" and define how it is properly applied.