Mal 3:10 Bring all the tithes into the storehouse, That there may be food in My house, and try Me now in this," says the LORD of hosts, "If I will not open for you THE WINDOWS OF HEAVEN and pour out for you such blessing that there will not be room enough to receive it.
It refers to the pouring out of rain from heaven. Israel was an agricultural nation. Without rain, it would be a national calamity, it would mean drought and famine.
Ge 7:11 In the six hundredth year of Noah's life, in the second month, the seventeenth day of the month, on that day all the fountains of the great deep were broken up, and THE WINDOWS OF HEAVEN WERE OPENED.
12 AND THE RAIN WAS ON THE EARTH forty days and forty nights.
Malachi was an Old Testament prophet. His job was to call the people of Israel back to their covenant or agreement with God. He was reminding them of what would happen if they were faithful to their agreement with God.
God had a contract or agreement with the nation Israel that if they were faithful to Him, God would do His part, He would bless them with rain.
De 28:12 "The LORD will open to you His good treasure, the heavens, to give the rain to your land in its season, and to bless all the work of your hand. You shall lend to many nations, but you shall not borrow.
Material blessings and prosperity were God's promise to Israel.
P.S. It is important when reading the Bible to realize the distinction between God's promises to Israelites in the Old Testament and God's promises to Christians in the New Testament. Never intrude yourself into something you are not a part of. Read the Bible plainly and normally and remember while all the Bible is FOR Christians, not all of it was written TO Christians. We can learn principles from Israel's Old Covenant ("All Scripture...is profitable" as per 2 Tim. 3:16) but be careful of claiming the promises indiscriminately.
