Rav Mari reports that Rabbi Yochanan had said, "He who indulges in the practice of eating lentils once in thirty days keeps away quinsy, but they are not good to be eaten regularly because by them the breath is corrupted." He used also to say that mustard eaten once in thirty days drives away sickness, but if taken every day the action of the heart is apt to be affected.
Berachoth, fol. 40, col. 1.
He who eats unripe dates and does not wash his hands will for thirty day be in constant fear, without knowing why, of something untoward happening.
P'sachim, fol. 111, col. 2.
The Rabbis have taught that the lighter kind of excommunication is not to last less than thirty days, and censure not less than seven. The latter is inferred from what is said in Num. xii. 14, "If her father had but spit in her face, should she not be ashamed seven days?"
Moed Katon, fol. 16, col. 1.
If we meet a friend during any of the thirty days of his mourning for a deceased relative, we must condole with him but not salute him; but after that time he may be saluted but not condoled with. If a man (because he has no family) re-marries within thirty days of the death of his wife, he should not be condoled with at home (lest it might hurt the feelings of his new partner); but if met with out of doors, he should be addressed in an undertone of voice, accompanied with a slight inclination of the head.
Ibid., fol. 21, col. 2.
During the thirty days of mourning for deceased friends or relatives, the bereaved should not trim their hair; but if they have lost their parents, they are not to attend to such matters until their friends force them to do so.
Ibid., fol. 22, col. 2.
And Haman told them of the glory of his riches and the multitude of his children" (Esth. v. 11). And how many children were there? Ray said thirty; ten had died, ten were hanged, and ten went about begging from door to door. The Rabbis say, "Those that went about begging from door to door were seventy; for it is written (1 Sam. ii. 5), 'They that were full have hired themselves for bread.'"
Meggillah, fol. 15, col. 2.
When Rabbi Chauena bar Pappa was about to die, the Angel of Death was told to go and render him some friendly service. He accordingly went and made himself known to him. The Rabbi requested him to leave him for thirty days, until he had repeated what he had been learning; for it is said, "Blessed is he who comes here with his studies
in his hand." He accordingly left, and at the expiration of thirty days returned to him. The Rabbi then asked to be shown his place in Paradise, and the Angel of Death consented to show him while life was still in him. Then said the Rabbi, "Lend me thy sword, lest thou surprise me on the road and cheat me of my expectation." To this the Angel of Death said, "Dost thou mean to serve me as thy friend Rabbi Yoshua did?" and he declined to intrust the sword to the Rabbi.
Kethuboth, fol. 77, col. 2.
If a man says to a woman, "Thou art betrothed to me after thirty days," and in the interim another comes and betroths her, she is the second suitor's.
Kiddushin, fol. 58, col. 2.
If one finds a scroll, he may peruse it once in thirty days, but he must not teach out of it, nor may another join him in reading it; if he does not know how to read, he must unroll it. If a garment be found, it should be shaken and spread out once in thirty days, for its own sake (to preserve it), but not for display. Silver and copper articles should be used to take care of them, but not for the sake of ornament. Gold and glass vessels hie should not meddle with--till the coming of Elijah.
Bava Metzia, fol. 29, col. 2.
Rabbi Zira so inured his body (to endurance) that the fire of Gehenna had no power over it. Every thirty days he experimented on himself, ascending a fiery furnace, and finally sitting down in the midst of it without being affected by the fire. One day, however, as the Rabbis fixed their eyes upon him, his hips became singed, and from that day onward he was noted in Jewry as the little man with the singed hips.
Ibid., fol. 85, col. 1.
An Arab once said to Rabbah bar bar Channah, "Come and I will show thee the place where Korah and his accomplices were swallowed up." "There," says the Rabbi, "I observed smoke coming out from two cracks in the ground. Into one of these he inserted some wool tied on to the end of his spear, and when he drew it out again it was scorched. Then he bade me listen. I did so, and as I listened heard them groan out, 'Moses and his law are
true, but we are liars.' The Arab then told me that they come round to this place once in every thirty days, being stirred about in the hell-surge like meat in the boiling caldron."
Bava Bathra, fol. 74, col. 1.
Rabbi Yochanan, in expounding Isa. liv. 12, said, "The Holy One--blessed be He!--will bring precious stones and pearls, each measuring thirty cubits by thirty, and polishing them down to twenty cubits by ten, will place them in the gates of Jerusalem." A certain disciple contemptuously observed, "No one has ever yet seen a precious stone as large as a small bird's egg, and is it likely that such immense ones as these have any existence?" He happened one day after this to go forth on a voyage, and there in the sea be saw the angels quarrying precious stones and pearls like those his Rabbi had told him of, and upon inquiry he learned that they were intended for the gates of Jerusalem. On his return he went straight to Rabbi Yochanan and told him what he had seen and heard.
"Raca!" said the latter, "hadst thou not seen them thou wouldst have kept on deriding the words of the wise!" Then fixing his gaze intently upon him, he with the glance of his eye reduced to a heap of bones the carcass of his body.
Ibid., fol. 75, col. 1.
He who lends unconditionally a sum of money to his neighbor is not entitled to demand it back within thirty days thereafter.
Maccoth, fol. 3, col. 2.
If a man has lost a relative, he is forbidden to engage in business until thirty days after the death. In the case of the decease of a father or a mother, he is not to resume work until his friends rebuke him and urge him to return.
Semachoth, chap. 9.
It is unlawful for one to enter a banqueting-house for thirty days after the death of a relative; but he must refrain from so doing for twelve months after the demise of either father or mother, unless on the behest of some higher requirement of piety.
But I know not whether there are thirty righteous men here and fifteen in the land of Israel, or vice versâ.
Chullin, fol. 92, col. 1.
Thirty days in a year are equivalent to a whole year.
Niddah, fol. 44, col. 2.