This isn't specific to 10% but I look to it as a good reason to give.
A passage that I look to for giving advice in the NT is:
1 John 3:17 But if anyone has the world's goods and sees his brother in need, yet closes his heart against him, how does God's love abide in him?
James as well.
James 2
15 If a brother or sister is naked and destitute of daily food,
16 and one of you says to them, "Depart in peace, be warmed and filled," but you do not give them the things which are needed for the body, what does it profit?
As Americans we (even if we are poor) are among those who have "the world's goods". Even at our poverty level most people in the third world nations could live like nobility.
While my youngest daughter was in high school she went on a mission trip to visit and help our missionaries in Mexico. When she came back she was depressed and I even found her with tears a time or two.
When I asked what was it that was upsetting her so. She said - Dad, I didn't realize how much we have, those people down there are so poor, I couldn't believe how poor they are and where and how they have to live and the clothes they wear. It was awful.
Most of the other kids who went had the same story.
It's one thing to see it on photos and slides, it's different in person.
She never again complained about her food, clothing, etc.
Give. It is its own reward.
HankD