How does the tithe that Christians commonly refer to as 10% of their total giving compare to Old Testament giving? Many people who give 10% see that as the end of their giving.
Freewill offerings were commonplace in the Old Testament era. The three tithes were never the ceiling of giving, merely the floor. And Malachi 3 speaks of robbing God by withholding tithes AND offerings. This means that even prior to the New Testament people with substantial assets were considered to be robbing God not only by withholding TITHES but OFFERINGS (freewill).
So while we are free to choose what we give, God also holds us accountable for it, and He knows and sees not only what we give but what we keep. Most of the passages we use to point out that God owns everything, not merely the tithe, are Old Testament passages. Hence it is not just a New Testament concept, though the model of the poor widow and the Macedonian church, giving beyond its ability in 2 Cor. 8, and the Acts 2 and 4 models clearly show an explosion of the lightning of God’s grace resulting in the thunder of people’s giving.
Certainly the abuses of “grace giving” are evident in the average giving of 2.6% in the most affluent society in human history. The fact that so many argue against giving the minimum of the tithe—much less anything substantially more—indicates how wrong our thinking is.
For further explanation of the three tithes in the Old Testament, see pages 174-179 of my book, Money, Possessions and Eternity.