http://www.shechem.org/torah/avot.html verse 12
12. At four periods pestilence increases: In the fourth year and the seventh year and in the year after the seventh year, and at the end of the Feast of Tabernacles every year.
"In the fourth year"--because of neglect of the Poorman's Tithe in the third year (Deuteronomy 14:28-30).
"In the seventh year"--because of neglect of the Poorman's Tithe in the sixth year.
"In the year after the seventh year"--because of transgressing the Torahs of the seventh year produce.
"At the end of the Feast of Tabernacles every year"--because of robbing the poor of the harvest gifts that are their due.
The frequency of famine is reflected in the fact that of the seven calamities said in the Mishnah to afflict the world because of sin, three are famines of various degrees of intensity: the "famine of drought," which does not affect the whole population, the "famine of panic," which affects all, and the "famine of utter destruction" (Avot 5:8). The traditional triad of major catastrophes consists of "pestilence, sword, and famine" (cf. Jer. 14:12; 21:7, 9; 24:10; Ezek. 6:11, etc.; compare the Hashkivenu and the Avinu Malkenu prayers). The fact that, given a choice of one of these three, David chose pestilence suggests that it was the least of them (II Sam. 24:14f.). Lamentations gives a preference in the scale of suffering to famine over the sword (4:9). This would indicate that famine was the greatest evil of all: it is in fact difficult to envisage the terrible suffering endured through famine in ancient times. The grim picture, given by R. Johanan, imaginative though it is, of the consequences of the seven-year famine predicted by *Elisha (II Kings 8:1) – that in the fourth year people would be reduced to eating unclean animals, in the fifth reptiles and insects, in the sixth their children, and in the seventh their own flesh (Ta'an. 5a) – is probably not so exaggerated as may appear. Both during the famine caused by the siege of Samaria by *Ben-Hadad and of Jerusalem by Nebuchadnezzar, the eating of human flesh is mentioned (II Kings 6:29; Lam. 2:20–31; 4:10).
Ashurbanipal, king of Assyria (669–27) claims that the Babylonians under siege by him ate their children. Similarly, Assyrian treaties threaten potential violators that they will bereduced to eating their children. Josephus mentions the eating of children in Jerusalem during the Roman War (Wars 6:201–13, cf. I Bar. 2:2ff.). A pathetic story is told of one of the wealthiest women of Jerusalem picking out grain from animal dung after the Roman War (Git. 56a). There are at least three historical references to famine caused by the observance of the Sabbatical year, one during the siege of Jerusalem by the forces of Antiochus IV (Ant. 12:378 = I Macc. 6:49–54), one in the war of Herod against Antigonus (ibid., 14:476) and one during Herod's reign (ibid., 15:7 – see also *Shemittah). The Midrash (Ruth Rabbah 1:4) enumerates ten famines which visited the world. It includes only seven of those mentioned in the Bible as due to drought, and makes up the complement by one ascribed
One of the three things "which the Holy One, blessed be He, proclaims in person" (Ber. 55a), famine was regarded as the direct result of transgressions. This is, of course, specifically mentioned in the Bible where the rule is that famine and drought are either threatened (Lev. 26:19f., 26; Deut. 11:17; 28:23; I Kings 17:1; Zech. 14:17) or suffered for sins. Amos (4:6ff.) interprets occurrences of these calamities as prods to repentance – warning notices of God's wrath aimed to bring the people to contrition and thus avert final destruction. The tendency of the rabbis was to make famine the punishment for specific transgressions – the failure to give the tithes and other dues from one's produce, as a kind of quid pro quo (Avot 5:8; Shab. 32b; for the contrary promise of abundance as a reward for bringing tithes – cf. Mal. 3:10–11). As a result, fasting and supplicatory prayers and fasts were instituted (see *Fasting and *Ta'anit – for biblical examples cf. Jer. 14:12 and Joel 2:14–15 for famine caused through pestilence) and the prayers of both pious individuals and people possessing special virtues were regarded as effective in bringing the drought to an end (BM 85b; TJ, Ta'an. 1:2, 65b). The rabbis permitted emigration from Ereẓ Israel in the case of famine, but only when it reached serious proportions (BB 91b; Gen. R. 25 end). Basing themselves on Genesis 41:50 the rabbis (Taan. 11a) forbade procreation during the years of famine.
11. Seven kinds of
punishment come into the world for seven important transgressions. If some give their tithes (27) and others
do not, a dearth ensues from drought and some suffer hunger while others are full. If they all determine to give
no tithes, a dearth ensures from tumult (28) and drought. If they further resolve not to give the dough−cake
(29), an exterminating dearth ensures. Pestilence comes into the world to fulfil those death penalties
threatened in the Torah, the execution of which, however, is within the function of a human tribunal (30), and
for the violation of the law regarding the fruits of the seventh year (31). The sword (32) comes into the world
for the delay of justice, and for the perversion of justice, and on account of the offence of those who interpret
the Torah, not according to its true sense (33). Noxious beasts come into the world for vain swearing (34), and
for the profanation of the Divine Name (35). Captivity comes into the world on account of idolatry,
immortality, bloodshed, and the neglect of the year of rest for the soil (31). 12. At four periods pestilence
grows apace: in the fourth year, in the seventh, at the conclusion of the seventh year, and at the conclusion of
the Feast of Tabernacles in each year: in the fourth year, for default of giving the tithe to the poor in the third
year (36); in the seventh year, for default of giving the title to the poor in the sixth year (37); at the conclusion
of the seventh year, for the violation of the law regarding the fruits of the seventh year (31), and at the
conclusion of the Feast of Tabernacles in each year, for robbing the poor of the grants legally assigned to them
Pirke Avot, Traditional Text