Exodus 30:15-16
30:15 The rich are not to increase it, and the poor are not to pay less than the half shekel when giving the offering of the Lord, to make atonement for your lives.
30:16 You are to receive the atonement money from the Israelites and give it for the service of the tent of meeting. It will be a memorial for the Israelites before the Lord, to make atonement for your lives.”