Genesis 17:17-19
Then Abraham fell upon his face, and laughed, and said in his heart, Shall a child be born unto him that is an hundred years old? and shall Sarah, that is ninety years old, bear?  And Abraham said unto God, O that Ishmael might live before thee!  And God said, Sarah thy wife shall bear thee a son indeed; and thou shalt call his name Isaac: and I will establish my covenant with him for an everlasting covenant, and with his seed after him.

Abraham and Sarah had tried to take things into their own hands, but they hadn’t messed up the covenant.  They hadn’t spoiled God’s plans.  Inwardly, Abraham doubted.  Ishmael is the son he had, so that is the son he thought God had to use.  But the covenant son, the God-given son would still come.  Even in that laughable state, a 100-year-old man and his 90-year-old wife, God would bring this promise to pass.  Despite Ishmael, that other son, God would give Isaac to Abraham and Sarah.

We make a lot of mistakes in our lives, too.  But that doesn’t undo the plans God has for us.  That doesn’t change how He can still work in our future.  That doesn’t disqualify us from receiving the promises.  Yes, Ishmael caused some problems.  There were consequences to face because of that.  It made some things more difficult for them.  But Isaac still came.  A nation still came.  A Savior still came.  Sometimes God has to work out His will despite us, but He still does work out His will.

So can we just get hold of the fact that God is faithful and He is always going to be faithful?  He already knows we’re going to fail Him.  He knows which significant ways we’re going to mess up.  But He also knows how He plans to work anyway.  He’s got everything figured out, and we can trust Him to handle it in His way.  We can still move forward.  We can still be part of what God is doing.  We can be faithful again.

God doesn’t go back on His word just because we fail.  After all, He’s not really depending on us for anything.  He’s got to do it if it’s going to happen at all.  It will always be His power accomplishing those hard and impossible things.  So let’s just be willing to submit.  Let’s just have faith.  Let’s not give up on ourselves when we’ve made a wrong choice.  Let’s allow God to use us for whatever He has for us to do.  And then we’ll get to see Him do something so amazing.  We’ll get to be part of what He is doing in our world, that grand plan He has for His people and His kingdom.