"Tithing."
http://ichthys.com 
Question:  
Can you tell me whether or not tithing is necessary for salvation?
Response:
Salvation is based entirely on faith in Jesus Christ. It has nothing whatsoever to do with any number of rituals or procedures now endemic in the Church, whether legitimate, illegitimate, or somewhere in between. Therefore, salvation is not in any way dependent upon tithing. Tithing was an Israelite ordinance established in the law of Moses, primarily for the support of the Levites and the Aaronic priesthood (Num.18:21-26; Deut.12:17). Tithing is no more operative in the present church than burnt offerings and other sacrifices (often mentioned in conjunction with tithes).
It is clear that Christian giving is to proceed from true capacity (2Cor.8:12b) and genuine desire to give (2Cor.9:7), not from the Old Testament formula of tithing. No doubt financial pressures are at the root of much organizational desire for tithing, but how dangerous to allow any circumstantial exigency to distort the clear meaning of the Word of God. After all, "... the love of money is a root cause of all types of evil" (1Tim.6:10).
Please have a look at the following links:
Is tithing net or gross?
Tithing and the Book of Life
Read your Bible:  Protection against Cults
Yours in Christ,
Bob Luginbill
http://ichthys.com