According to Genesis 4:1-4, before the law was ever given to Moses, Abel, and Cain brought the first fruits of their labor to God.

And again in Genesis 14, we find that Abraham tithed - before the law! The first thing Abram did after they had conquered the enemy and took the spoils was tithe the spoils. Then Melchizedek blessed him.

Genesis 14:18-20 - "Then Melchizedek king of Salem brought out bread and wine; he was the priest of God Most High. And he blessed him and said: Blessed be Abram of God Most High, Possessor of heaven and earth, and blessed be God Most High, Who has delivered your enemies into your hand."

Tithing didn't begin with the law. The law only explained the tithe.

Hebrews 7:1-8 - "For this Melchizedek, king of Salem, priest of the Most High God, who met Abraham returning from the slaughter of the kings and blessed him, to whom also Abraham gave a tenth part of all, first being translated "king of righteousness," and then also king of Salem, meaning "king of peace," without father, without mother, without genealogy, having neither beginning of days nor end of life, but made like the Son of God, remains a priest continually. Now consider how great this man was, to whom even the patriarch Abraham gave a tenth of the spoils. And indeed those who are of the sons of Levi, who receive the priesthood, have a commandment to receive tithes from the people according to the law, that is, from their brethren, though they have come from the loins of Abraham, but he whose genealogy is not derived from them received tithes from Abraham and blessed him who had the promises. Now beyond all contradiction the lesser is blessed by the better. Here mortal men receive tithes, but there he receives them, of whom it is witnessed that he lives".

We cannot say that tithing is just under the law because this happened four hundred years before the law. Hebrews 5:6 tells us that Jesus is a High Priest after the order of Melchizedek. He has all the rights that Melchizedek had, which included the right to bless the tithe. In the Church Jesus not only receives our tithes, He blesses them and then blesses us just as Abraham was blessed. If Melchizedek blessed Abraham, then how much more will Jesus bless us!

Galatians 3:14 - "that the blessing of Abraham might come upon the Gentiles in Christ Jesus, that we might receive the promise of the Spirit through faith. We have to activate this blessing. We do that by faith. Faith is action and what we believe will only work when we add action to it".

James 2:17 - "Thus also faith by itself, if it does not have works, is dead".

Giving is the action we put to our faith and that bring the blessing of God in our finances. When we stand on the promises of God and put action to our faith we have rights as "givers" to stand against the enemy and we know that God will "rebuke the devourer for our sakes"

Malachi 3:10-12 - is clearly for Isreal under the law, but because God is a good God, He will bless us also when we give by faith.