Rom 4:19-21
19 Abraham didn't focus on his own impotence and say, "It's hopeless. This hundred-year-old body could never father a child." Nor did he survey Sarah's decades of infertility and give up. 20 He didn't tiptoe around God's promise asking cautiously skeptical questions. He plunged into the promise and came up strong, ready for God, 21 sure that God would make good on what he had said.