A man made a promise to carry a cross to the top of a mountain if a certain wish of his was satisfied.
God granted him what he asked for.
He had the cross made, and set out on his climb. After a few days he found that the cross weighed more than he had reckoned. He borrowed a saw to cut off a good section of the wood. On reaching the top of the mountain he noted that, separated by a gulf, there was another mountain.
Over on the other side, everything was peace and tranquility, but he needed a bridge to get over there.
He tried to use the cross-but it was a bit too short.
And then he realized that the piece he had cut off was exactly what was missing to enable him to cross the abyss.