Twenty-five children is the highest number there should be in a class for elementary instruction. There should be an assistant appointed, if there be forty in number; and if fifty, there should be two competent teachers. Rava says, "If there be two teachers in a place, one teaching the children more than the other, the one that teaches less is not to be dismissed, because if so, the other is liable to lapse into negligence also." Rav Deimi of Nehardaa, on the other hand, thinks the dismissal of the former will make the latter all the more eager to teach more, both out of fear lest he also be dismissed, and out of gratitude that he has been preferred to the other. Mar says, "The emulation of the scribes (or teachers) increaseth wisdom." Rava also says, "When there are two teachers, one teaching much but superficially, and one teaching thoroughly but not so much, the former is to be preferred, for the children will, in the long run, improve most by learning much." Rav Deimi of Nehardaa, however, thinks the latter is to be preferred, for a mistake or an error once learned is difficult to unlearn; as it is written in 1 Kings xi. 16, "For six months did Joab remain there with all Israel, until he cut off every male in Edom." When David asked Joab why he killed only the males and not the females, he replied, "Because it is written in Deut. xxv. 19, 'Thou shalt blot out the male portion of Amalek.'" "But," said David, "we read 'the remembrance of Amalek.'" To this Joab replied, "My teacher taught me to read zachar and not zeichar," i. e., male, and not remembrance. The teacher of Joab was sent for; and being found guilty of having taught his pupil in a superficial manner, he was condemned to be beheaded. The poor teacher pleaded in vain for his life,
for the king's judgment was based on Scripture (Jer. xlviii. 10), "Cursed be he that doeth the work of the Lord deceitfully, and cursed be he that keepeth back his sword from blood.
Bava Bathra, fol. 21, col. 1.