Contemporary English Version (CEV)
Abraham, who chose to honor Melchizedek, made it clear who was superior when he gave 10% of what he had to Melchizedek.
In the same way, when we give money to the glory of God, we're making a declaration about who is worthy of more honor. By freely sacrificing, we admit that it isn't all about us -- what we have is meant to be directed for the glory of God. We aren't trying to build up monuments for ourselves. We're trying to contribute to God's glory, and so we give freely for God's honor.