Seeing no obvious solutions, the first blonde gets on her knees, presses her hands together and prays "God, please give me the strength to cross this river," so god makes her buff and she swims across.
The second blonde then begins to pray and says, "God, please give me aid in crossing this river." All of a sudden, a log big enough to support her weight alone drifts down and she manages to paddle across.
The third blonde then falls to he knees and says "God, give me the intelligence to cross this river," so god turns her into a brunette and she crosses the bridge.
Moral: God's help depends on how you pray.