Moses wrote a historical account of Israel's grumbling against the Lord and the resulting wandering in the desert. Moses described how the Lord gave the Levites the tithes of the people. The tithe of the tithes went to the priests.
In comparison to the gods of the Mesopotamia and Canaan, God did not need the tithes and offerings to sustain Him. The false gods' priests would deceptively say the food was to feed the gods but would secretly feed themselves. God was upfront with His people and gave the food and offerings to His ministers.
We serve a living God who needs nothing from us. He just desires our love and devotion. He loves us so much that He sent His Son to die and redeem us and gave us part of Him, His Spirit, to live in us.