Charles Spurgeon Commentary Malachi 3:10

"Bring ye the whole tithe into the store-house, that there may be food in my house, and prove me now herewith, saith Jehovah of hosts, if I will not open you the windows of heaven, and pour you out a blessing, that there shall not be room enough [to receive it]." — Malachi 3:10 (ASV)

They had kept themselves poor by their own stinginess. If they had behaved rightly towards God, he would have enriched them with the bounties of his providence; the very windows of heaven would have been thrown open to give them abundance for all their needs.