Sarah laughed, doubting that she would have a child because she and Abraham were both so old.
After her initial doubt she then chose to trust and believe that what the angels had spoken was true.
She believed enough to do her part. To “receive strength to conceive”. I think this scripture is telling us that Isaac wasn’t conceived as Jesus was. That his mother, Sarah was a willing, proactive participant in the conception of Isaac.
Sarah showed faith after her initial doubt.
God came through on His part.
Has the Spirit led you to do something seemingly impossible? Have you doubted that it will actually come to pass?
Move past the doubting and start showing your faith. Get on board with the plans God has for you.