Deuteronomy 28:12

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. The Lord shall open unto thee good treasure. The seasonable supply of the early and latter rain was one of the principal means by which their land was so uncommonly fruitful.

Thou shalt lend unto many nations, and thou shalt not borrow - i:e., thou shalt be in such affluent circumstances as to be capable, out of thy superfluous wealth, to give aid to thy poorer neighbours.