Midrash su Salmi 91:11

And Moses said unto the children of Israel: “See, the Lord hath called by name Bezalel the son of Uri” (Exod. 35:30). May it please our masters to teach us: How far must a person go to eliminate mixed materials (shatnez)?¹A biblical injunction prohibiting the wearing of a garment made of wool and linen. The law also proscribes the planting of heterogeneous plants in the same field. R. Simeon the son of Yohai concluded from the verse Neither shall there come upon thee a garment of two kinds of stuff mingled together (Lev. 19:19) that a man is prohibited from donning an outer garment of mixed material even though he puts it on over a hundred other garments. However, if he should put it on beneath his other garments, without the mixed material touching his body, he is permitted to do so, for it is said: Neither shall there come upon thee a garment of two kinds of stuff mingled together. The words upon thee signify that it may not be worn as an outer garment but that it may be placed underneath (i.e. closer to the body). The Holy One, blessed be He, said to Israel: Keep My commandments and My statues. Why? Because the consequence of a good deed is another good deed, but the result of committing a sin is another sin. Ben Azzai stated that one good deed results in another good deed, and one sin produces another sin. R. Meir said: For every good deed a man performs, an angel is assigned to watch over him. If he does one good deed, one angel is assigned to him, and if he performs many good deeds, many angels are assigned to him, as it is said: For he will give His angels charge over thee (Ps. 91:11). Every time a man increases the number of good deeds he performs, he adds to his good name. You find that a man is known by three names: the name by which his father and mother call him, the name by which other men call him, and the one he earns for himself; the most important name is the one he earns for himself.²His good deeds are apparent to all.

(Fol. 11) Our Rabbis were taught: "When the community of Israel is in trouble and one withdraws himself from them [refusing to share their sorrow], two ministering angels who accompany each man lay their hands upon his head and say: 'The Baraitha we are taught: "When the community when in distress shall not live to see the relief of the community.' " In another Baraitha we are taught that when the community is in distress one must not say: 'I will go to my house, eat, drink and make myself comfortable'; for concerning him the passage reads (Is. 22, 13) And behold {there are) joy and gladness, in staying oxen, and killing sheep, eating flesh, and drinking wine; 'Let us eat and drink; for tomorrow) we must die'; and immediately follows: Truly this iniquity shall not be purged from you till you die. But a man must suffer (deny himself enjoyment), when the community suffers: for thus we find that Moses afflicted himself when the community suffered; as it is said (Ex. 17, 12) But when the hands of Moses became heavy, they took a stone, and put it under him, and he sat thereon. Did not Moses possess a pillow or bolster upon which he could have sat down? Yea; but Moses said thus: 'Since Israel lives in trouble I must therefore share their woes.' And he who afflicts himself in sympathy with the community, will live to see the relief of the community. One might perhaps say: 'Who will testify that I did not share the suffering of the community?' He should know that the stones and beams of his very house will bear testimony to this fact; as it is said (Hab. 2, 11) For the stone will cry out of the wall, and the beam out of the woodwork will answer it." In the college of R. Shila it was said that the two angels who accompany a man will testify against him; as it is said (Ps. 91, 11) For his angels will he given charge concerning thee. R. Chidka says: "The soul of man will testify against him; as it is said (Micah 7, 4) Keep the doors of thy mouth from her that lieth in thy bosom." Still others say that the members of a man's body will testify against him; as it is said (Is. 43, 10) Ye are my witnesses, saith the Lord.

R. Juda b. Nachmeni, the interpreter of Resh Lakish lectured again: "What is the meaning of the passage (Micha 7, 5) Trust ye not in a friend, put ye not confidence in a familiar friend? This means, if the evil spirit say to thee, Go and commit a sin for the Holy One, praised be He! will forgive thee, be not persuaded, as it is said: Trust ye not in an evil (Ro'a); put ye not confidence in a familiar friend, this refers to none else than the Holy One, praised be He! as it is said (Jer. 3, 4) My father, Thou art; the friend (Aluph) of my youth art Thou. Perhaps one will say, who will testify against me? The stones and the timbers of his house will bear witness against him, as it is said (Hab. 2, 11) For the stone will cry out of the wall, and the beam out of the wood (work) will answer it. "We are taught in a Baraitha: R. Shila says the two angels which accompany a man will testify against him, as it is said (Ps. 91, 11) For his angels will he give charge concerning thee, to guard thee on all thy ways. R. Zerika says the soul of a man will testify against him, as it is said (Mie. 7, 5) From her that lieth in thy bosom guard the doors of thy mouth. What is this that lieth in a man's bosom? We must say, it is the soul. The sages say: "The members of a man's body testify against him, as it is said (Is. 43, 12) And ye are My witness, saith the Lord, and I am God."