Abraham = "father of many" (NIV footnotes)
I find this fascinating. God changes Abram's name to "father of many" before he has any children. God's reasoning included the past tense: "I have made you a father of many". It was already done by God's reasoning but had yet to happen (a year later). So here is Abraham, changing his name at 99 years old to 'Father of Many' while he has no children. People must have thought he was crazy: "There goes the childless 'Father of Many'."
While reading the Bible, I'm struck by what jerks many of the characters are; they just keep doing stupid things over and over. It's comforting to know that they are mess up just like we are. It's also comforting that God keeps his promises to them (and us) often in spite of them (and us). We play a very small part in whether God keeps his promises to us. He is faithful. His kindness knows no end. That’s just what he’s like.
This reminds me of a Graham Cooke teaching. Graham talks about stepping out into God's promises for us. God speaks a promise over us and then he begins to interact with us from the standpoint of the promise fulfilled. God changed Abram's name to Abraham before he had children. God referred to his reasoning using the past tense--"I have made you…" though the event of Abraham becoming a father was still a year away.
Paul picks up on this same story in Romans 4:17b "the God who gives life to the dead and calls things that are not as though they were."
God often does the same thing in our lives that he did in the life of Abraham; he speaks promises to us which make zero sense based on our current situations. This is where faith enters the picture; we step into a spiritual reality based on God’s promises--often in spite of our circumstances. It’s our job to believe; it’s his job to work out the details.