What does the Bible say about giving?

Giving shows he is Lord of our lives.  First and foremost, God wants us to give because it shows that we recognize he is truly the Lord of our lives.
Every good and perfect gift is from above, coming down from the Father of the heavenly lights, who does not change like shifting shadows. James 1:17, NIV) Everything we own and everything we have comes from God. So, when we give, we simply offer him a small portion of the abundance he has already given to us.
Giving is an expression of our thankfulness and praise to God. It comes from a heart of worship that recognizes everything we have and give already belongs to the Lord.
God instructed Old Testament believers to give a tithe, or a tenth because this ten percent represented the first, most important portion of all they had. The New Testament does not suggest a certain percentage for giving, but simply says for each to give "in keeping with his income."


When we give freely to God, we receive freely from God.  Give, and it will be given to you. A good measure, pressed down, shaken together and running over, will be poured into your lap. For with the measure you use, it will be measured to you. (Luke 6:38, NIV)
One man gives freely, yet gains even more; another withholds unduly, but comes to poverty. (Proverbs 11:24, NIV) God promises to bless us over and above what we give and also according to the measure that we use to give. But, if we hold back from giving with a stingy heart, we hinder God from blessing our lives.


God values our offerings differently than men do.  Jesus sat down opposite the place where the offerings were put and watched the crowd putting their money into the temple treasury. Many rich people threw in large amounts. But a poor widow came and put in two very small copper coins, worth only a fraction of a penny. Calling his disciples to him, Jesus said, "I tell you the truth, this poor widow has put more into the treasury than all the others. They all gave out of their wealth; but she, out of her poverty, put in everything—all she had to live on." (Mark 12:41-44, NIV)
In God's eyes, the value of the offering is not determined by its amount. The passage says that the wealthy gave large amounts, but the widow's "fraction of a penny" was of much higher value because she gave all that she had. It was a costly sacrifice. Notice that Jesus did not say she put in more than any of the others; he said she put in more than all the others.