God in His love for Israel had frequent censuses taken of them, so that He might accurately estimate His possession. In scarcely half a year they were twice counted, once shortly before the erection of the Tabernacle, and the second time a month after its dedication. [422] On the first day of the month of Iyyar, Moses received instructions to take a census of all men over twenty who were physically fit to go to war. He was ordered to take Aaron as his assistant, so that in case he should overlook some of the men Aaron might remind him of them, for "two are better than one." They were also to take as their subordinate assistants Eleazar and Ithamar, Aaron's sons, and a man each from the several tribes. These twelve men were appointed not only to conduct the census, but also to look after the spiritual welfare of their respective tribes, the sins of which would be upon their heads unless, with all their powers, they strove to prevent them. Moses and Aaron nevertheless adjured the princes of the tribes, in spite of their high rank, not to tyrannize over the people, whereas, on the other hand, they admonished the people to pay all due respect to their superiors. [423] The names of these twelve princes of the tribes indicated the history of the tribes they represented. The prince of the tribe Reuben was called Elizur, "my God is a rock," referring to the ancestor of this tribe, Reuben, Jacob's son, who sinned, but, owing to his penance, was forgiven by God, who bore his sin as a rock bears the house built upon it. The name of Elizur's father was Shedeur, "cast into the fire," because Reuben was converted to repentance and atonement through Judah, who confessed his sin when his daughter-in-law Tamar was about to be cast into the fire. The prince of the tribe of Simeon was named Shelumiel, "my God is peace," to indicate that in spite of the sin of Zimri, head of this tribe, through whom four and twenty thousand men among Israel died, God nevertheless made peace with this tribe. The prince of the tribe of Judah bore the name Nahshon, "wave of the sea," the son of Amminadab, "prince of My people," because the prince received this dignity as a reward for having plunged into the waves of the Red Sea to glorify God's name. The tribe of Issachar had for its prince Nethanel, "God gave," for this tribe devoted its life to the Torah given by God to Moses. Accordingly Nethanel was called the son of Zuar, "burden," for Issachar assumed the burden of passing judgement on the lawsuits of the other tribes. Corresponding to the occupation of the tribe of Zebulun, its prince was called Eliab, "the ship," son of Helon, "the sand," for this tribe spent its life on ships, seeking "treasures hidden in the sand."