Musar על ברכות 108:25

ועשית עמדי חסד ואמת . The main ingredient of חסד, kindness, is that it be performed without expectation of a reward. Only when performed thus is one called generous; otherwise one is simply a trader. There is no greater virtue than that of חסד. This is why a person must train himself to practice this virtue until it becomes second nature to him. Not only should he perform acts of kindness for the dead, but even more so for the living. By doing so he will emulate the virtues practiced by G–d Himself who constantly performs acts of kindness without any thought of compensation. Concerning this David has said in Psalms 63,4: "For truly Your kindness is better than life itself; my lips declare Your praise." David meant that whereas when human beings practice acts of altruistic loving-kindness, this is almost always with the dead. You, G–d, perform deeds of loving-kindness for the living, by the very fact that You grant us our life. What could we possibly do in the way of compensating You!? All we can do is to pay You lip-service, extol Your virtues in song and prayer. Rashi referred to this in his commentary on 49,21, where he interprets the אמרי שפר as an allusion to the song of victory sung by Deborah after Israel defeated Sisera under her leadership. G–d performs the miracles and all we can do in return is to acknowledge them with our lips.

Let us return to our principal subject, the three reasons for animal sacrifice. We have stated that one reason is that the sacrifices are the instruments of achieving atonement. The sacrifices which perform this function are the חטאת, עולה, ואשם. The second reason we need sacrifices is to be able to take advantage of the phenomenon of תמורה, to enable G–d on occasion to override the horoscopic influences we are subject to by substituting some other creature in our place. The sacrifice which is most likely to accomplish this is the קרבן תודה, offering of thanksgiving. We are taught (Berachot 54b) that there are four categories of people who have to offer such a type of offering because they have been saved from dangers by G–d through personal intervention, i.e. through the phenomenon we have described as תמורה. I have explained elsewhere that the mystical dimension of a miraculous escape is due to the phenomenon known as תמורה וחליפין. The third function which we hope that sacrifices perform for us is achieved through the daily public offerings, the תמידים as well as the מוספים on the Sabbaths, the Holy Days, and the New Moon. These days possess inherent sanctity.