Tithing is giving one tenth of your income back to God through your local church. There are a few passages in the Bible where we get the idea of tithing as a good general starting point for giving back to God for all He’s given us: Genesis 14:20; Leviticus 27:30; Deuteronomy 14:22. Some would argue that these are all Old Testament examples that are not reiterated in the New Testament, and therefore we are not required to tithe. But if you look at the early church in the New Testament, they gave a lot more than a tithe, whether it was required or not. Sometimes they sold their own possessions and lands to help each other or other churches for the sake of Christ.
The point isn’t whether or not we’re required to tithe, the point is that we should be open-handed when it comes to God and His work. I’ve read somewhere that tithing isn’t giving so much as it is returning. God owns everything and He lets us use it, so we ought to be using all of it properly. A tithe is hardly a drop in the bucket, and isn’t the only thing you should be doing to give (or return) to God. Tithing is not the ceiling of giving to God. God owns everything in the first place, and Christians are called to be good stewards of all that God has given us. We are to use God’s stuff well, and more than just the monetary part.
Tithing is not a protection fee, nor is it for appearances or to gain favors. While God will certainly reward you for wholeheartedly honoring Him (Matthew 6:1-4), if you’re only doing it for the reward, you’re not doing it for the right reason.
Tithing is a way to give God precedence in your life, particularly monetarily. Tithing helps your church pay its staff and missionaries. Tithing gives your church the freedom to minister to its members and to the surrounding community. Tithing helps further the Gospel. Tithing helps put you in a right attitude about your stewardship of God’s stuff.
Related: How Much Should I Give God?