I will give a thought that I haven't read yet on here.
The act of tithing was started long before the Mosaic Law.
Abraham paid tithes to the King of Salem, Melchizedek.
18 And Melchizedek king of Salem brought out bread and wine; now he was a priest of God Most High.
19 He blessed him and said, "Blessed be Abram of God Most High, Possessor of heaven and earth;
20 And blessed be God Most High, Who has delivered your enemies into your hand." He gave him a tenth of all.
The Mosaic law, I believe is based on this act. However, Abraham gave not because their was a commandment to give, not because he was being forced, rather Abraham gave out the abundance of his heart. Abraham was blessed, so then he blessed the priest of the Most High God with a tenth of his spoils.
How does this apply today? Yes, the NT does not specifically say, pay your tithes. Nor does it say, do not pay your tithes. Some of the people who say we are not commanded by the NT are the ones who play instruments in church when it does not command us too. (This is just a point).
The other point is this. The writer in Hebrews points out that Christ's priesthood is not of the Levitical Priesthood. But of the order of Melchizedek which is forever. Now, there is a lot of speculation of who Melchizedek was, but the writer of Hebrews states that Christ is even greater than Melchizedek, becoming our high priest.
If Christ is now our high priest, should we then give a tenth of what we are blessed with? I believe so. To say that we are not commanded by NT too pay tithes is lacking in the eternal perspective of trying to advance God's Kingdom.
People say that they give when they are moved. Shoot if I gave based on my emotions I would give about 5% of the time. That's the truth.
Here's a quick story. A short time ago my wife and I were struggling financially. We knew that when we paid our tithes that not only would the tithe come out but also the over draft fee. I struggled with it. I really did. I would say that God doesn't want us to pay anymore than we have too. Or ai would say, why doesn't God put the money into the bank. Or where is that mystery check at that everyone else talks about getting?
Then one night God told me to shut up and he broke me down. See I was expecting money as my blessing, as my miracle. But you know what he told me. Your miracle is that you still have a roof over your head, you still have food to eat, you still have gas to put in the car, you still have clothes to put on your back.... I

like a little baby before God. I was like the lame man before the temple who was expecting Peter and John to give him alms. I was expecting God to give me financially. But Peter and John gave the lame man God and in that process gave him back his life. God was giving me back what we really needed. Not finaces, rather food and the things neccessary to live... I was ashamed.
It was about 3 month's later of listening to God that my wife was awarded with an unexpected promotion that gave her a pretty nice increase. Then the next month later we were able to restructure some debt and now for over a year and half we have been blessed. We are not wealthy by any means. But God still provides. And I know it's because we continued to pay our tithes.