There is a doctrine that has circulated within my fellowship for many years called the Shekel and a Half doctrine.  Those espousing to this doctrine claim that in addition to paying tithes on ones income (10%), believers need to pay an additional 5%.  It is often said that the additional 5% is for the upkeep of the church, or to fund a church building program.  Exodus 30:11-16 is appealed to for Biblical support:

The Lord spoke to Moses: 12 “When you take a census of the Israelites according to their number, then each man is to pay a ransom for his life to the Lord when you number them, so that there will be no plague among them when you number them. 13 Everyone who crosses over to those who are numbered is to pay this: a half shekel according to the shekel of the sanctuary (a shekel weighs twenty gerahs). The half shekel is to be an offering to the Lord. 14 Everyone who crosses over to those numbered, from twenty years old and up, is to pay an offering to the Lord. 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. 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.”

The setting of this pericope is the post-exodus wilderness wandering of the children of Israel.  God ordered Moses to count the people.  Every male age 20 and up was required to pay a half shekel of silver to the Lord as a ransom for his life, otherwise a plague would come upon them and kill them.  The money collected was to be given to the Levites and used for the maintenance of the tabernacle (Exodus 38:25-28 gives an account of how much silver was collected, and how it was used).  That this passage is being used illegitimately by those endorsing the Shekel and a Half doctrine is clear for the following reasons:

First, the text does not say a shekel is equivalent to a tithe (10%), so there is no objective measurement provided on which to conclude that a half shekel is equivalent to a half tithe (5%).  We are only told the weight of a shekel (6 grams, or 1/5 of an ounce).  Any percentage that one might attribute to a half shekel would be arbitrary.

Secondly, and more importantly, it is clear that the half shekel is a fixed amount, not a percentage at all.  YHWH did not command that men ages 20 and up give a certain percentage of their silver to the Lord, but only 10 gerahs (3 grams, or 1/10 of an ounce).  We do not know the precise value of 10 gerahs, but it could not have been much given the fact that rich and poor alike were required to pay the same amount.

Thirdly, the half shekel payment was a singular event.  It was not an ongoing payment for the continued upkeep of the tabernacle.

Lastly, the primary purpose of the half shekel payment was to purchase one’s own ransom from the Lord to avoid experiencing a divine plague.  God, having no need of money, however, “donated” the ransom money to the Levites for the service of the tabernacle.  Since we have already received the ultimate atonement for our lives in the death of Jesus Christ, there is no need for any further payment.  To suggest that there is, is to deny the sufficiency and finality of Christ’s atoning death.

In conclusion, the Shekel and a Half doctrine is a misuse of Scripture.  While it is appropriate for one to give additional money to their local assembly for building programs or the upkeep of their building, there is no Biblical basis for requiring such giving, yet alone a certain percentage.  All such giving should be voluntary.