Musar su Salmi 145:9

The sage said, "Mercy is the result of kindliness and honesty." In regard to it, Solomon the Wise spake when he exhorted to mercy and compassion (Prov. xxiv. 11), "If thou forbear to deliver them that are born unto death." A beautiful feature of this quality in connection with the Creator, exalted and hallowed may He be, is that He is merciful in dealing with all His creatures. Thus it is said (Ps. cxlv. 9), "The Lord is good to all, and His tender mercies are over all His works." In the book of Al-Kuti, it is said, "Spare no effort to deliver those who are confronted with death." Again he said, "Do not wrong the weak, for their Protector is God, the mighty One." He said, "Prosperous are they whose heart is ever merciful and meek," and again we find therein, "He who is not merciful will die by the hand of one who is merciless."

To have mercy upon all of the creatures: He must also have his mercy extend to all the creatures. He [should] not disgrace them nor destroy them. As behold, the Highest Wisdom is spread over all the creatures - the inanimate, the growing (plants), the living (animals) and the speaking (people). And we are warned about disgracing food for this reason. And about this thing it is fitting that [just] like the Highest Wisdom does not disgrace anything in existence and everything was made from There, as it is written, "You made all of them with wisdom" - so [too, should] the mercy of a person be over all of His creations, may He be blessed. And for this reason was the holy Rebbe punished: Since he did not pity the young calf that was hiding with him and said to it, "Go, you were created for this," afflictions came upon him (Bava Metzia 85a). As they were from the side of judgement; since behold, mercy protects from judgement. And when he had mercy on a weasel and said, "It is written (Psalms 145:9), 'and His mercies are over all of His creatures,'" he was saved from the judgement - since the light of Wisdom was spread over him and the afflictions withdrew. And upon this way, he [should] not disgrace anything in existence from that which exists, as all of them are with Wisdom. And [so] he [should] not uproot a plant except for a need nor kill an animal except for a need. And [then] he [should] chose a nice death, with a checked knife, to have mercy in as much as is possible.

And you will discern and understand the great virtue of this quality of mercy in that the Creator conducts Himself with that quality with all His creatures, as it is said: "And His tender mercies are over all His works" (Ps. 145:9).