Musar su Genesi 41:22

We similarly find that when Jacob was embattled against the Emorites that he referred to his conquest of the city of Shechem as something he had acquired by means of "my sword and my bow" (Genesis 48,22). There was another element to this battle: The prayer Jacob offered up helped him succeed. Onkelos translates the words בחרבי ובקשתי as בצלותי ובבעותי, "with my prayer and my entreaty." It was Jacob's custom that whenever he was involved in a confrontation he would employ three kinds of weapons which our Rabbis have referred to as מלחמה, דורון, תפלה. These may be considered as Jacob's "secret weapons." The weapon called דורון, was gifts to charity; the weapon called מלחמה was the struggle against his evil urge; the weapon called תפלה needs no homiletical interpretation. These three weapons together are what are popularly known as הקול קול יעקב. The weapon of charity is also alluded to in a Biblical passage describing soldiers going into battle. Psalms 85,14 speaks of: צדק לפניו יהלוך וישם לדרך פעמיו, "Charity goes before him as he sets out on his way." We also have a verse in Exodus 30,12 ונתנו איש כופר נפשו, suggesting that a man can use his charitable gifts to help him overcome his blood-guilt, i.e. to save him from danger in war. The fact that only men over the age of twenty had to make this contribution is a clear indication that once one is of military age it may become a life-saver.