Exodus 30:11 And יהוה spoke to Moses saying, 12 When you take אֶת־ the sum (census) of the Children of Israel, then every man will give a ransom for his soul to ליהוה; that there will be no plague among אֹתָם them after you number אֹתָם them. C-MATS
Question: What is the concern about counting the people of Israel? The Torah teaches that it is forbidden to count יהוה’s people in the ordinary manner, and that when it is necessary to conduct a census, it should be done by having the people contribute items, which would then be counted. In the case of the census in the Wilderness, the people, rich and poor alike, were called upon to contribute half a shekel each, for the construction and upkeep of the Tabernacle. The status of Israel is elevated by its contributions to charitable causes, and this is why they were counted by having the entire nation join in contributing to a sacred cause. Chumash
Question: Why does the Torah forbid counting the people? The evil one has power over numbered things because man looks at the number not יהוה, and pestilence comes upon them, as we find in David’s time. King David took a census of all the people and יהוה punished the nation because of David’s sin. Chumash
Exodus 30:13 Everyone that must be numbered will give half a shekel (1/5 of an ounce of silver), by the standard of the shekel of the sanctuary: (a shekel is twenty gerahs) a half shekel will be the offering to ליהוה. C-MATS
Question: When was this half-shekel collected each year? The annual half shekel gift to pay for the communal offerings was collected during the month of Adar, so that the funds would be ready in time for the month of Abib (Passover).
Exodus 30:14 Everyone that must be numbered twenty years old or above will give an offering to יהוה. C-MATS
Question: What does this teach us? The Torah teaches you here that no one under 20 years old goes out to serve in the army or is counted among men. Chumash