The wisdom of Kabbalah doesn’t explain that giving is good, since this contradicts the child’s desire.
You cannot tell a child something that contradicts the child’s spirit and natural way. Instead, bring the child a game in which he or she will have to discover that it is better to treat others favorably, that one gains more by it, and that it pays off, meaning that it is rewarding because society encourages it and respects the child for doing so.
The positive attitude toward giving must be consistent. It is wrong to show a child that now we will treat him or her well after acts of giving, but tomorrow that response may change.
Children must learn that this is the truth of life, that it is Nature’s way, and through the study, the change will occur within them.