Looking only at the money leaving a person's possession shows a reduction in wealth. But Zakat meets the needy person's need. It is therefore meaningful spending, not simply money being lost.
The connection is:
giving Zakat → meeting need → goodness and reward.
The needy person's need is the intermediary in this explanation. Its creation belongs to Allah, not to a voluntary act by the rich or poor person. That is why this intermediary is treated as absent and Zakat is attached to intrinsic goodness.
- Zakat: Wealth Spent to Meet a Need