My dear friend, my short answer is that I do not believe that failing to observe the ordinances of the law, such as giving the tithe, constitutes sin. This does not mean that Christians today are not to give…much to the contrary. However, the actual “tithe” was one of the Jewish ordinances of the law; and believers today are no longer under the law, but we are now under grace. Let me explain and show the Scriptures which lead me to say these things. The law was given by God to Israel in the first place, not to demonstrate our ability to be perfect under the law, which is God’s standard of perfection; but the law was really given, in part, to show us that we are all sinners and in need of a Savior, the Lord Jesus Christ. It was also a kind of guide or “tutor” for His people prior to the coming of Christ. In Galatians 3:24-25 (NKJV) we read: “But before faith came, we were kept under guard by the law, kept for the faith which would afterward be revealed. Therefore the law was our tutor to bring us to Christ, that we might be justified by faith. But after faith has come, we are no longer under a tutor.” And in Romans 6:14, we see clearly that Born Again Christians are no longer under law, but under grace.

Galatians 3:11-14 clearly shows us that we are not to look to the law for righteousness, but rather to faith. I believe that it is of critical importance that born again Christians do not try to add anything to the grace of the Gospel by placing themselves once again under the law as a requirement for pleasing God, because we simply cannot keep the law in ourselves (see Galatians 3:1-9). The law only condemns us, showing that all of us are sinners deserving of judgment (Romans 3:23; Romans 7:10-11). But Christ Jesus, in His death and resurrection has satisfied the righteous demands of the law in His own body. All is done for us by Christ through grace (unmerited favor), and all that is left for us is to believe. And when we believe on Christ Jesus as our Savior, He gives us the Holy Spirit to come dwell in our hearts, imparting to us a new life…a new creation (2 Corinthians 5:17). The only way we can be right with God, then, is to come to Christ Jesus in faith, whereupon we are clothed in His righteousness. If we begin to believe that we must keep part or all the law while we are yet on the earth, we are as much as stating that faith alone in Christ’s work of redemption on the cross was not enough, and therefore we must try once again to keep the law, even though we cannot keep that law perfectly.  But, my friend, if you are born again, Christ has done all that is required by the law…indeed, He has fulfilled the law, and our only part in the matter is to repent of our sins and believe. Now, does this mean that the law ceases to exist, or that the law is somehow bad? Not at all (see Matthew 5:17-18; also see Romans 7:7). But, when Christ went to the cross for us, bled and died for us, and rose again, we who believe are now to reckon ourselves dead (our old man) in Him, and risen with Him in new life (the new nature). Thus, we are, by faith alone, delivered from the demands of the law (see Romans 7:6). We are now to walk according to the Spirit of God who dwells in us.  

But now, what does the Bible teach us about giving in the New Testament? I believe that the Lord has provided an even higher standard for us than the law, and one that we can only meet if we are in Christ, through the power of the Holy Spirit, and not according to our abilities under our old natures. God asks not for the tithes, but for all of us…our time, our bodies, and yes, our wealth, to be used for Him, for we are not our own, but are redeemed (1 Corinthians 6:19-20; Romans 12:1;1 Peter 1:18-19). Christians are to give according to their means, as the Lord has prospered them, and that with a cheerful heart.  We do this, not to achieve some measure of personal righteousness because we have none in ourselves…Christ Jesus was “raised for our justification,” and we are only righteous in Him, through faith in His finished work on the cross for us. For more on Christian giving, you might consider Philippians 1:5-7, Galatians 6:8, and 2 Corinthians 9:5-8. None of this that I am speaking of is tithing, but rather “Christian giving”, and there is a big difference!

In summary, my dear friend, born again Christians give to the poor and to support the ministry of the Word because the Holy Spirit has placed the love of Christ in our hearts. What makes this different than tithing is that the latter was a requirement for God’s people under the Law, but Christ Jesus has completed the Law. Giving according to our abundance, and cheerful giving is certainly a standard for Christians, but we do not do this to keep the OT statute, for man would tend to try once again to be right with God by keeping the law in our flesh, and we simply cannot do this. You will find that the tithe is not given as a requirement for blessing in the NT church. This topic is covered nicely in 2 Corinthians 9:6-15.  I’ll quote verses 6-7, “But this I say, He which soweth sparingly shall reap also sparingly; and he which soweth bountifully shall reap also bountifully. Every man according as he purposeth in his heart, so let him give; not grudgingly, or of necessity: for God loveth a cheerful giver.”  (SF)  (672.5)