There is the law, and then there is the spirit of the law. In Matthew 23:23, Jesus addressed this issue when He gave His only New Testament statement on tithing. He rebuked the Pharisees for being meticulous in tithing a tenth of each little tiny seed they owned while neglecting the more important parts of the law: justice, mercy, and faith. He did not tell them to abandon their faithful tithing, but He encouraged them to expand their thinking to include the needs of others.
Tithing is biblical. Jesus is the High Priest who receives your tithes (Hebrews 7:8), and tithing will release a supernatural blessing in your life so great that you will not be able to contain it (Malachi 3:10). Above the mere obedience to the duty of the law, however, is the spirit of the law.
As New Testament Christians, we should move beyond the obligation of tithing to showing mercy through the giving of offerings above the tithe to support the needy worldwide. The tithe sustains the local church, and offerings advance world outreach. Start with the tithe, out of duty and obedience. End with the offering, out of love, compassion, and the spirit of the law.