“As the rain cometh down, and the snow from heaven, and returneth not thither, but watereth the earth, and maketh it bring forth and bud, that it may give seed to the sower, and bread to the eater: So shall my word be that goeth forth out of my mouth: it shall not return unto me void, but it shall accomplish that which I please, and it shall prosper in the thing whereto I sent it. For ye shall go out with joy, and be led forth with peace: the mountains and the hills shall break forth before you into singing, and all the trees of the field shall clap their hands. Instead of the thorn shall come up the fir tree, and instead of the brier shall come up the myrtle tree: and it shall be to the LORD for a name, for an everlasting sign that shall not be cut off.” (Isa 55:10-13) KJV
We often think of this as meaning that any time the Word of God is presented it will bring forth results, even if they are not immediate results.
The truth is, however, the passage is telling us that God will keep the promises that He has made to His people.
His Word will not come back to Him without having brought to pass that which God purposed to do when He made promise to His people.
For this reason we should trust God deeply, intensely, and eternally.
-- My Bible And I, June 23, 2008, Jason Skipper at the Pastoral Musings blog (also reprinted in the Voice of Faith, December 2008, p. 3)