Moses sent his father-in-law Jethro back to his home, shortly before the revelation on Mount Sinai. He thought: "When God gave us a single commandment of the Torah in Egypt, the Passover, He said, 'There shall no stranger eat thereof.' Surely Jethro may not look on when God bestows on us the whole Torah." Moses was right: God did not want Jethro to be present at the revelation. He said: "Israel was in Egypt, bound to work with clay and bricks, at the same time as Jethro was sitting at home in peace and quiet. He who suffers with the community shall share their future joys, but he who does not share the sufferings of the community shall not take part in their rejoicing." 
God had not only good cause to delay the giving of the Torah until after the departure of Jethro, but the time He chose to bestowing it was also chosen for a good reason. Just as a female proselyte, or a woman freed from captivity, or an emancipated slave, may not enter wedlock before she has for three months lived as a free Jewess, so God also waited three months after the deliverance of Israel from the bondage and the slavery of Egypt, before His union with Israel on Mount Sinai.  God furthermore treated His bride as did that king who went to the marriage ceremony only after he had overwhelmed his chosen bride with many gifts. So did Israel first receive manna, the well, and the quails, and not till then was the Torah granted them. Moses, who had received this promise when God had first appeared to him, viz., "When thou has brought forth the people out of Egypt, ye shall serve God upon this mountain" - waited most longingly for the promised time, saying, "When will this time come to pass?" When the time drew near, God said to Moses, "The time is at hand when I shall bring about something entirely new."
This new miracle of which God spoke was the healing of all the sick among the Jews. God had wanted to give the Torah to the Jews immediately after the exodus from Egypt, but among them were found many that were lame, halt, or deaf; wherefore God said: "The Torah is without a blemish, hence would I not bestow it on a nation that has in it such as are burdened with defects. Nor do I want to wait until their children shall have grown to manhood, for I do not desire any longer to delay the delight of the Torah." For these reasons nothing was left Him to do, but to heal those afflicted with disease. In the time between the exodus from Egypt and the revelation on Mount Sinai, all the blind among the Israelites regained their sight, all the halt became whole, so that the Torah might be given to a sound and healthy people. God wrought for that generation the same miracle which He will hereafter bring about in the future world, when "the eyes of the blind shall be opened, the ears of the deaf shall be unstopped, the lame man leap as an hart, and the tongues of the dumb sing."  Not only physically was this generation free from blemishes, but spiritually, too, it stood on a high plane, and it was the combined merits of such a people that made them worthy of their high calling. Never before or after lived a generation as worthy as this of receiving the Torah. Had there been but one missing, God would not have given them the Torah: "for He layeth up wisdom for the righteous; He is a buckler to them that walk uprightly." 
For one other reason did God delay the revelation of the Torah. He had intended giving them the Torah immediately after their exodus from Egypt, but at the beginning of the march through the desert, great discord reigned among them. Nor was harmony established until the new moon of the third month, when they arrived at Mount Sinai; whereupon God said: "The ways of the Torah are ways of loveliness, and all its paths are paths of peace; I will yield the Torah to a nation that dwells in peace and amity."  This decision of God, now to give them the Torah, also shows how mighty is the influence of penance. For they had been sinful upon their arrival at Mount Sinai, continuing to tempt God and doubting His omnipotence. After a short time, however, they changed in spirit; and hardly had they reformed, when God found them worthy of revealing to them the Torah.
The third month was chosen for the revelation, because everything that is closely connected with the Torah and with Israel is triple in number. The Torah consists of three parts, the Pentateuch, the Prophets, and the Hagiographa; similarly the oral law consists of Midrash, Halakah, and Haggadah. The communications between God and Israel were carried on by three, Moses, Aaron, and Miriam. Israel also is divided into three divisions, priests, Levites, and laymen; and they are, furthermore, the descendants of the three Patriarchs, Abraham, Isaac, and Jacob. For God has a preference for "the third": It was the third of Adam's sons, Seth, who became the ancestor of humanity, and so too it was the third among Noah's sons, Shem, who attained high station. Among the Jewish kings, too, it was the third, Solomon, whom God distinguished before all others. The number three plays a particularly important part in the life of Moses. He belonged to the tribe of Levi, which is not only the third of the tribes, but has a name consisting of three letters. He himself was the third of the children of the family; his own name consists of three letters; in his infancy he had been concealed by his mother throughout three months; and in the third month of the year, after a preparation of three days, did he receive the Torah on a mountain, the name of which consists of three letters.