Rashi writes (28:11) that before going to sleep, Yaakov placed stones around his head because he was afraid that he may be attacked by wild animals. If he was truly scared of the potential danger, how did the placement of small stones around his head - which would clearly be ineffective in the event of a real attack - allay his anxiety?
Our Rabbis explain that a person who truly trusts in G-d understands that after he has done all that he is realistically able to do in a certain situation, the outcome at that point is in G-d's hands and there is no reason to worry about it. In Yaakov's case, although the rocks around his head offered inadequate protection, they were all that was available for Yaakov to use to protect himself, so once he had done all that was in his power, he went to sleep confident in G-d's protection.
This is an important lesson for all of us. Many times we feel that we must be in complete control, we want everything to work out exactly the way we plan. We must realize that although we need to put in a realistic amount of effort, we must always know that it is Hashem who is ultimately in control.
Rabbi Isaac Farhi