Rabbi Meir had a disciple named Sumchus, who in every case assigned forty-eight reasons why one thing should be called clean and why another should be called unclean, though Scripture declared the contrary. (A striking illustration of Rabbinical ingenuity! )
Eiruvin, fol. 13, col. 2.
Forty-eight prophets and seven prophetesses prophesied unto Israel, and they have neither diminished nor added to that which is written in the law, except the reading of the Book of Esther.
Meggillah, fol. 14, col. 1.
The Rabbis teach that in future (in the days of the Messiah) all Scripture will be abolished except the Book of Esther, also all festivals except the feast of Purim. (See Menorath Hamaor, fol. 135, col. 1.)
By forty-eight things the law is acquired. These are study, attention, careful conversation, mental discernment, solicitude, reverential fear, meekness, geniality of soul, purity, attention to the wise, mutual discussion, debating, sedateness, learning in the Scripture and the Mishna, not dabbling in commerce, self-denial, moderation in sleep, aversion to gossip, etc., etc.
Avoth, chap. 6.