What does "offering" mean?
An offering is giving over and beyond the tithe. The Bible says that by giving generously, we are able to "take hold of the life that is truly life." You aren't really living unless you are freely giving.
"Command them to do good, to be rich in good deeds, and to be generous and willing to share. In this way they will lay up treasure for themselves as a firm foundation for the coming age, so that they may take hold of the life that is truly life." - 1 Timothy 6:18-19