To tithe is to give God 10 percent of what he has given to you, and an offering means to give above and beyond the tithe. Tithes and offerings usually come in the form of monetary giving but can be anything of importance to you, including time, talents and gifts.
Christian tithing is not a commandment in the New Testament like it was under the Mosaic Law for the Israelites. Instead, Paul instructs Christians in 1 Corinthians to "set aside a portion of their income as an offering." It states that god wants his followers to tithe and offer to him with cheerful and thankful hearts.