“Sarah laughed to herself, saying, “After I have become old, shall I have pleasure, my lord being old also?'” (Genesis 18:12)
Now it was Sarah’s turn to laugh at the promise of God! Abraham had done the same thing in the last chapter (17:17 “Abraham fell on his face and laughed’) when God told him that he would have a son by Sarah. So BOTH of these chosen people laughed in disbelief at God’s promise! NO WONDER they called the child who was born, Isaac, which means “laughter”! Talk about an ironic name!
This name was a reminder to Abraham and Sarah of God’s faithfulness to His promise, even when they did not believe. As much as we might be tempted to idealize the faith of Abraham and Sarah, the truth is that God did NOT reward them according to their faith. Indeed, they even literally laughed at His promise. But God was faithful to His word anyway.
We can thank Him that the same thing is true today. God’s faithfulness to us, and to what He has promised us, is NOT based on how faithful WE are to Him. Beware of doctrines which emphasize how you get what you “earn” by faith. Not many of us would fare very well under such a system! And thank God that is not what He gives us. II Timothy 2:13 reminds us: “If we are faithless, He remains faithful, for He cannot deny Himself.” God is faithful to hold us, to keep us, and to bless us in countless ways, even — and especially — when we don’t deserve it. Even when like Abraham and Sarah, we might sometimes laugh in disbelief at His promise.