Exodus 30:11-16 New Revised Standard Version (NRSV)
The Half Shekel for the Sanctuary
11 The Lord spoke to Moses: 12 When you take a census of the Israelites to register them, at registration all of them shall give a ransom for their lives to the Lord, so that no plague may come upon them for being registered. 13 This is what each one who is registered shall give: half a shekel according to the shekel of the sanctuary (the shekel is twenty gerahs), half a shekel as an offering to the Lord. 14 Each one who is registered, from twenty years old and upward, shall give the Lord’s offering. 15 The rich shall not give more, and the poor shall not give less, than the half shekel, when you bring this offering to the Lord to make atonement for your lives. 16 You shall take the atonement money from the Israelites and shall designate it for the service of the tent of meeting; before the Lord it will be a reminder to the Israelites of the ransom given for your lives.