Ibid., fol. 43, col. 2.

Four are in duty bound to return thanks to God:—­They that have returned from a voyage at sea (Ps. cvii. 23, 24, 31); those who have traveled in the desert (verses 4-8); they who have recovered from a serious illness (verses 17-21); and those that are liberated from prison (verses 10-15).

Berachoth, fol. 54, col. 2.

If one does not walk, say four cubits, before falling asleep after a meal, that which he has eaten, being undigestible, causes foulness of breath.

Shabbath, fol. 41, col. 1.

Four have died in consequence of the seduction of the serpent:—­Benjamin, the son of Jacob; Amram, the father of Moses; Jesse, the father of David; and Chileab, the son of David.

Ibid., fol. 55, col. 2.

    These four are reckoned to have died on account of original sin,
    and not solely because of actual transgression, which, says
    Rashi, they never committed.

The traveler who is overtaken with the approach of Sabbath-eve before he has completed his journey should hand over his purse to a Gentile to carry; and if there be no Gentile at hand, let him stow it away on his ass.  As soon as the nearest halting-place is reached, those burdens which may be lifted on the Sabbath should then be removed, and then the cords should be slackened that the rest may slip off of its own accord.

Ibid., fol. 153, col. 1.

Here the Gemara very graciously appends a direction as to the disposal of the purse, in case the traveler should happen to be on foot and have no Gentile attendant.  He may take care of it himself, provided he halt at every other step and deposit it on the ground, for at least a distance of four cubits.

A master is bound to rehearse a lesson to his pupil four times.

Eiruvin, fol. 54, col. 2.

Alas for the power which prepares a grave for its possessor, for there is not a prophet who hath not in his lifetime witnessed the decadence of four kings; as it is said (Isa. i. 1), “The vision of Isaiah ... in the days of Uzziah, Jotham, Ahaz, and Hezekiah, kings of Judah” (see also Hosea i. 1).

P’sachim, fol. 87, col. 2.

Once Rav Pappa and Rav Hunnah partook together of a common meal, and as the latter ate only one morsel the former ate four.  After this, when Rav Hunnah and Ravina ate together, the latter devoured eight portions to the other’s one, upon which Rav Hunnah jocularly remarked, “A hundred (Rav) Pappas to one Ravina.”

P’sachim, fol. 89, col. 2.

No food may be eaten on Passover-eve from the time of the offering of the evening sacrifice (in order, i.e. that abstinence may whet the appetite for the Matsoth).  Even the poorest in Israel may not break his fast till the hour of reclining; nor is he to partake of less than four glasses of wine, even though he has been reduced so low as to subsist on the porridge doled out by public charity.