"And it came to pass after seven days that the waters of the flood were upon the earth" (Gen. vii. 10). Why this delay of seven days? Rav says they were the days of mourning for Methuselah; and this teaches us that mourning for the righteous will defer a coming calamity. Another explanation is, that the Holy One—blessed be He!—altered the course of nature during these seven days, so that the sun arose in the west and set in the east.
Ibid., fol. 108, col. 2.
The first step in transgression is evil thought, the second scoffing, the third pride, the fourth outrage, the fifth idleness, the sixth hatred, and the seventh an evil eye.
Derech Eretz Zuta, chap. 6.
Seven things cause affliction:—Slander, shedding of blood, perjury, adultery, pride, robbery, and envy.
Erchin, fol. 17, col. 2.
A ram has but one voice while alive but seven after he is dead. How so? His horns make two trumpets, his hip-bones two pipes, his skin can be extended into a drum, his larger intestines can yield strings for the lyre and the smaller chords for the harp.
Kinnim, chap. 3, mish. 6.
Rav Chisda said, The soul of a man mourns over him the first seven days after his decease; for it is said (Job xiv. 22), "And his soul shall mourn over him."