2. Is tithing a New Testament principle?
Tithing began before the law was introduced. The Law simply regulated the tithe. Abraham tithed to Melchizedek, 400 years before the time of Moses and the Law

3. Hebrews 7:1-10 (NASB)
1 For this Melchizedek, king of Salem, priest of the Most High God, who met Abraham as he was returning from the slaughter of the kings and blessed him, 2 to whom also Abraham apportioned a tenth part of all the spoils, was first of all, by the translation of his name, king of righteousness, and then also king of Salem, which is king of peace.

4. Hebrews 7:1-10 (NASB)
3 Without father, without mother, without genealogy, having neither beginning of days nor end of life, but made like the Son of God, he remains a priest perpetually. 4 Now observe how great this man was to whom Abraham, the patriarch, gave a tenth of the choicest spoils. 5 And those indeed of the sons of Levi who receive the priest’s office have commandment in the Law to collect a tenth from the people, that is, from their brethren, although these are descended from Abraham.

5. Hebrews 7:1-10 (NASB)
…8 In this case mortal men receive tithes, but in that case one receives them, of whom it is witnessed that he lives on. 9 And, so to speak, through Abraham even Levi, who received tithes, paid tithes, 10 for he was still in the loins of his father when Melchizedek met him.

6. Is tithing a New Testament principle?
The tithe is not clearly reinforced in the New Testament the way it is in the OT, though giving absolutely is.
However, it is not clearly abolished either.

7. Matthew 23:23 (NLT)
“What sorrow awaits you teachers of religious law and you Pharisees. Hypocrites! For you are careful to tithe even the tiniest income from your herb gardens, but you ignore the more important aspects of the law—justice, mercy, and faith. You should tithe, yes, but do not neglect the more important things.”

8. Is tithing a New Testament principle?
Paul also carries over the concept of tithing as described in the law into the church. 1 Corinthians 9:13-14 (NASB) 13 Do you not know that those who perform sacred services eat the food of the temple, and those who attend regularly to the altar have their share from the altar? 14 So also the Lord directed those who proclaim the gospel to get their living from the gospel.

9. Is tithing a New Testament principle?
The clearest NT pattern of giving:
2 Corinthians 9:6-7 (NIV) 6 Remember this: Whoever sows sparingly will also reap sparingly, and whoever sows generously will also reap generously. 7 Each man should give what he has decided in his heart to give, not reluctantly or under compulsion, for God loves a cheerful giver.

10. Is tithing a New Testament principle?
The clearest NT pattern of giving:
Jesus said…
Matthew 6:21 (NASB) “For where your treasure is, there your heart will be also.”