In spite of what the people had neglected to do, God invited them to begin to do right. Apparently, there was insufficient food for the Levites and the poor. God invited the people to test Him to see what He would do.
“Bring ye all the tithes into the storehouse, that there may be meat in mine house, and prove me now herewith, saith the LORD of hosts, if I will not open you the windows of heaven, and pour you out a blessing, that there shall not be room enough to receive it.” – Malachi 3:10
You may find it interesting that the Israelites in the Old Testament did not tithe 10%, they tithed 20-30%, depending on which historian you listen to.
The New Testament model of giving is that every person gives to others as they are able (Hebrews 13:16; Luke 6:38; 2 Cor. 9:6-8), and that they give to the one who teaches the Word (Galatians 6:6).
It is safe to say that the New Testament model is that we give willingly, to those who have need, out of all of our excess.
We should pray and ask how much God wants us to give directly to our church, and then we should give out of our excess to brothers, sisters, widows, orphans, and whoever else we can. Also, we should give cheerfully (2 Cor. 9:7), not out of fear of being cursed.