God calls us to do the impossible on purpose! The whole point of what God is calling us to do is that we cannot do it ourselves. If there was any way we could do it ourselves, it would not be from God. He isn't interested in us living mediocre lives, completing mundane tasks in our own strength, wisdom, and ability. Because when we do that, all people see is us. They look at what we've done and say, "Good job! You did great! I'm so proud of you."
What God wants to hear people say is, "There is no way on earth that YOU could have done THAT. God had to have done something miraculous for that to have happened."
With apologies to the Army slogan, God does NOT want us to "be all we can be." He wants us to be all that He can be through us.
Let that sink in for a moment. Through the Holy Spirit, the same power that uttered the Word which created the universe dwells in us. The power that brought forth life in all its glorious diversity energizes our creativity. The power that set mountains in place fills our limbs with strength. The love great enough to go to the cross on our behalf fills us with love and forgiveness for those who have wronged us.
The Israelites didn't have the Holy Spirit dwelling in them, but they had God with them. Visibly with them in the form of the cloud by day and the pillar of fire by night that led them in the wilderness. Yet they missed the fact that entering the Promised Land was not dependent on their military strength, but on God's power.
What are you absolutely dependent on God to do in your life today?