Luke 1:18-19
And Zacharias said unto the angel, Whereby shall I know this? for I am an old man, and my wife well stricken in years.  And the angel answering said unto him, I am Gabriel, that stand in the presence of God; and am sent to speak unto thee, and to shew thee these glad tidings.

Gabriel had brought glad tidings to Zacharias.  This was good news.  His prayer was going to be answered.  He and his wife were going to have a son, and it would be no ordinary child, but one who would be used greatly by God.  This was a special and privileged thing that was happening, but all Zacharias could focus on was how it couldn’t possibly work out.

But Gabriel’s message had come from God Himself, and Zacharias would have done well to consider the source of the message he was given.  God knew exactly who he was.  He knew how old he was and how old his wife was.  He knew the pain of their past and the future of their child.  Surely such a thing as age would not stop God’s plan from being accomplished.

God’s will will be accomplished in our lives not because of who we are or despite the limitations we have.  God’s will is done because it is His will.  He plans it and brings it to pass in our lives, and usually it has very little to do with us.  God has got the future figured out.  He’s considered all the details.  He has the power and the ability and the wisdom to do what He says He will do.  All we really have to do is trust Him and believe Him and do our part in obedience to Him.

The reason we can trust so surely in the promises and the things God says is because He is the source of those things.  He is a faithful God who cannot lie or fail.  He is the one in control of our lives.  He is the one who is at work in and through us.  We don’t really have to believe in ourselves or think that we are able to do anything.  We don’t have to be something certain and specific for God to use us, because He knows all that we are and all that we can be.  May we just be willing to trust God to do what He says He will do, believing that He is able.