We humans love simplicity. We reduce intricate complexities to black and white, ignoring the intricate complexities of nature and reducing the supernatural to a set of rules that would make a great board game. We do the same thing with the Bible - we paint over the whole with whatever flavor we wish to taste. The joint nature of Abraham's blessing often escapes notice. We often let Sarah play a background role in Abraham's story. But God didn't relegate her to the sidelines. He told Abraham, "As for Sarai your wife, you shall not call her name Sarai, but Sarah shall be her name. I will bless her, and moreover, I will give you a son by her. I will bless her, and she shall become nations; kings of peoples shall come from her" (Genesis 17:15-16). The promise was for both. Also, God told Abraham that he could not call him "my" princess anymore. She is a princess, with or without Abraham.