The people going on from thence, and being again tried with want of water, hardly restrained themselves from destroying their leader. Then Moses, under divine orders, striking with his rod the rock at the place which is called Horeb, brought forth an abundant supply of water. But when they came to Raphidin, the Amalekites destroyed numbers of the people by their attacks. Moses, leading out his men to battle, placed Joshua at the head of the army; and, in company with Aaron and Hur, was himself simply to be a spectator of the fight, while, at the same time, for the purpose of praying to the Lord, he went up to the top of a mountain.
But when the armies had met with doubtful issue, through the prayers of Moses, Joshua slew the enemy until nightfall. At the same time, Jothor, Moses' father-in-law, with his daughter Sepphora (who, having been married to Moses, had remained at home when her husband went into Egypt), and his children, having learned the things which were being done by Moses, came to him. By his advice Moses divided the people into various ranks; and, setting tribunes, centurions, and decurions over them, thus furnished a mode of discipline and order to posterity.
Jothor then returned to his own country, while the Israelites came on to Mount Sinai. There Moses was admonished by the Lord that the people should be sanctified, since they were to hearken to the words of God; and that was carefully seen to. But when God rested on the mountain, the air was shaken with the loud sounds of trumpets, and thick clouds rolled around with frequent flashes of lightning. But Moses and Aaron were on the top of the mountain beside the Lord, while the people stood around the bottom of the mountain.
Thus a law was given, manifold and full of the words of God, and frequently repeated; but if any one is desirous of knowing particulars regarding it, he must consult the original, as we here only briefly touch upon it. “There shall not be,” said God, “any strange gods among you, but you shall worship me alone; you shall not make to time any idol; you shall not take the name of your God in vain; you shall do no work upon the Sabbath; honor your father and your mother; you shall not kill; you shall not commit adultery; you shall not steal; you shall not bear false witness against your neighbor; you shall not covet anything belonging to your neighbor.”
Source: Sacred History (New Advent)