Here are some verses on tithing ...
The first example of tithing is found in Genesis 14:17-20 (by Abraham) - this is also mentioned in Hebrews 7:1-6 - so it would seem that tithing (a tenth) is of enough importance to mention it here again in Hebrews.
Jacob also gave a tenth in Genesis 28:16-22
Leviticus 27:30-33 laws concerning the tithe
Numbers 18:26
Deuteronomy 12:6-8; 14:22; 26:13
Nehemiah 10: 35-39
The most famous verse for tithing is found in Malachi 3:8-10 "Will a man rob God? Yet you have robbed Me! But you say, In what way have we robbed You? In tithes and offerings." "Bring all the tithes into the storehouse, that there may be food in My house ..." "prove Me now in this ... If I will not open for you the windows of heaven and pour out for you such blessing that there will not be room enough to receive it."
Did the practice of tithing a tenth carry over to the New Covenant??
Jesus seemed to imply that the practice should continue in Matthew 23:23 "These you ought to have done, without leaving the others undone."
Verses on giving and/or taking up a collection ...
Matthew 5:42 "Give to him who asks you, and from him who wants to borrow from you do not turn away."
Matthew 19:21 "Jesus said to him, "If you want to be perfect, go, sell what you have and give to the poor, and you will have treasure in heaven; and come, follow Me."
Luke 12:33,34 "Sell what you have and give alms; provide yourselves money bags which do not grow old, treasure in the heavens that does not fail, where no thief approaches nor moth destroys. For where your treasure is, there your heart will be also."
I Corinthians 16:1,2 "Now concerning the collection for the saints, as I have given orders to the churches of Galatia, so you must do also: On the first day of the week let each one of you lay something aside, storing up as he may prosper, that there be no collections when I come."
In 2 Corinthians 8,9 we are given the example of the Macedonians who gave willingly and generously despite their poverty, we also see the purpose of giving, the policies of giving, the readiness of giving, principles in giving and promises from giving.
The most famous verse from the above passage II Corinthians 9:7 "So let each one give as he purposes in his heart, not grudgingly or of necessity (compulsion); for God loves a cheerful giver."
I Timothy 6:18 "Let them do good, that they be rich in good works, ready to give, willing to share ..."
I think we need to realize that God owns ALL our money and we need to be asking Him what to do with our paycheck each week - prayerfully considering where to give so that we are ready to give and no one need "compell" us to give.
I have found that we cannot outgive the Lord - once we realize that ALL we have belongs to Him - and we open up our pocketbook, our home, our talents, our food etc etc we are never without the means to give generously over and above even the ten percent apportioned in the Old Testament (actually I have heard that those who followed the Law were giving closer to 30 percent).
My two cents