His good treasure, to wit, the heaven or the air, as it here follows, which is God's storehouse, where he treasures up rain or wind or other things for man's use. See Job 38:22 Psalms 33:7.
Related Commentaries of Deuteronomy 28:12
Deuteronomy 28:12
12 The LORD shall open unto thee his good treasure, the heaven to give the rain unto thy land in his season, and to bless all the work of thine hand: and thou shalt lend unto many nations, and thou shalt not borrow.