1. Is it in the Bible?
Yes. (there are 585 references to "offering", however all but about a dozen are found in the old covenant, and the few found in the new covenant make it clear that we are NOT to make offerings, since Christ has made the new covenant offering....
Heb 10:10 By the which will we are sanctified through the offering of the body of Jesus Christ once for all.
2. What do we believe it means?
The laws and principles of God state that every believer needs to make a payment--and offering to God. this is done by giving to your local church.
3. What does it really mean?
If we look at the verses of the Bible that speak about "offering" we can clearly see that this practice belongs to the old covenant. In the old covenant, God gave Israel a way to make payment (offering means "payment") that he would honor--to forgive their sin. god told Israel to amok offerings of blood and meat (of certain animals) as well as grain (which was made into "shewbread"). God accepted these as payment for the sin of Israel--but as the new testament says--these were imperfect, earthly offerings. We as christians know what our payment for sin is (or at least we ought to!) Jesus' blood on the cross (he also called His flesh "meat" and His body "bread") is the new covenant offering for sin and as it concisely says in Hebrews..
Heb 10:18 Now where remission of these is, there is no more offering for sin.
The questions we ask to the very big tradition of making "offerings" in Christian church is:
1. Why do we utilize old testament conventions as operational principles for the new covenant church?
2. If we believe "offerings" is "of the law" a need must be fulfilled, how do we magically transfer the offering of animals and grain into money?
The new testament does say Christians need to make an offering--and it is very specific--
Heb 13:15 By him therefore let us offer the sacrifice of praise to God continually, that is, the fruit of our lips giving thanks to his name.
An offering of praise is due to God. Not money.
We often hear the teaching that mixes the concept of 'offering" with the new covenant principles of "giving". The new testament tells us to give to the poor and in fact to give to the work of ministry in the church. what is missing (once again!) is the new testament concept that God could choose anyone to do ministry at any time. In the new testament, the church took up collections--but read the purpose they collected for--!!
1Co 16:1 Now concerning the collection for the saints, as I have given order to the churches of Galatia, even so do ye.
The collecting of money or goods was specifically directed as god gave instruction--toward the poor. the tradition of "offerings" within the church takes advantage of the believers Godly desire to give--and turns it into a law.
The tradition of offering makes Christians give to themselves,
for purposes that are not part of the new covenant.