The Lord commanded them to fulfill their covenant duties. The Lord also said, “bring all the tithe”, which means some people may not be bringing the correct portion to the Lord. They are compromising their faith. As if to motivate the people, the Lord said “test Him and see” if He’d provide for them if they gave.
It’s interesting that the word “test” (ָבּ ַחן ) would have the sense here of proving something, such as testing a new product or a plan. To test God would be an act of faith; and that would be contrary from the wilderness generation who tested God because they did not believe him. Test Him by faith. God was calling the people to act on his promises, to prove them true. God was saying, “obey and see that I am faithful in delivering all that I promised.”
God would open the floodgates of heaven and pour out blessings on them. For what? Just because they brought back what God gave them in the first place? It seemed like a very imbalanced deal, and God was on the short end. God was here calling the people to trust Him, and that they would have to demonstrate their trust by giving Him what is due.
Experience the Power of Prophecy as a gift to open your mind to receive the Mind of Christ.