In his article On Wealth and Worry, Craig Blomberg explains Jesus’ teaching on money from the Sermon on the Mount (Matthew 6). The whole paper is worth reading, but the summary at the end is particularly helpful. Blomberg’s analysis about money is captured as follows:
A major barometer of spiritual maturity and obedience involves one’s financial priorities. Careful scrutiny of a person’s checkbook ledger may be more telling than various outward forms of piety, if one is trying to determine who is truly committed to Christ. Matthew 6:24 suggests that materialism may be one of the greatest competitors with God for human allegiance. A. Kodjak elaborates persuasively: mammon “is the most direct channel for self-assertion, the establishment of security, the acquisition of a sense of superiority over other mortals, and thus the presumed removal of the curse of mortality.” Second, it has a lasting power outliving the one who accumulated it and thus functions as a “surrogate immortality.”
…The mentality which promises God a certain percentage and then assumes one is free to do whatever one wants with the rest is seriously misguided. We need to recover a sense of “whole-life stewardship.” Scripture never mandates a tithe (or any other percentage of giving) for the NT age (i.e., after Jesus’ death and resurrection), but it does call believers to give generously and sacrificially, which for most everyone in the middle-class or above surely ought to suggest ten percent as a bare minimum. Most should seriously consider giving far more either to churches or to other Christian organizations and individuals. The concept of a graduated tithe seems to fit well with Paul’s understanding of believers’ responsibilities in 1 Cor 16:2 and 2 Cor 8:12-13. In other words, the more money one makes, the higher percentage one would give away.
If this is a topic that interests you, Blomberg’s book Neither Poverty Nor Riches expands on the topic by surveying all of the verses in Scripture on wealth. Also, read about other articles about Christian giving.