Verse explainer
God's word doesn't fail — but the promise is about God's purposes being achieved, not that every sermon or prayer produces the result we expect.
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.
BSBso My word that proceeds from My mouth will not return to Me empty, but it will accomplish what I please, and it will prosper where I send it.
The plain meaning
Isaiah 55 is an invitation from God to the exiled and the spiritually hungry (vv. 1-3). The rain-and-snow image in vv. 10-11 grounds the promise: just as precipitation never returns to the sky without first watering the earth and producing a harvest, God's spoken word never returns empty. The assurance is rooted in God's sovereign intention — "that which I please" and "whereto I sent it." It is a promise about the reliability of God's own purposes, not a blank guarantee that any particular human use of scripture will automatically succeed. The context is God reassuring his people that the covenant promises he has spoken — restoration, forgiveness, abundance — will come to pass. The word here is God's own issued decree, not a magical property of scripture quoted in any context.
The common misreading
What the commentators say
Gill reads the verse as referring primarily to the word of the Gospel — which comes from God, falls according to his direction, and never returns without effect. Whether it softens a heart or hardens it, whether it converts sinners or leaves them without excuse, it always accomplishes what God sent it to do. Gill also allows a secondary reference to Christ himself as the eternal Word, who returned to heaven not empty but having secured the full salvation of his people.
JFB stress that rain falling on a desert is not wasted — it fulfils some purpose of God even when the visible result is nil to us. So the gospel word on a hard heart either works conversion in time or leaves the hearer without excuse. JFB also note that the fullest fulfilment of vv. 11-13 is eschatological, pointing to Israel's final restoration and the conversion of the nations, as Isaiah develops in chapters 11 and 60.
The word behind it
"Empty" or "void" — from a root meaning emptiness, without result or purpose. Gesenius notes it describes a return with nothing to show, as a messenger coming back empty-handed. The word frames the whole guarantee: God's word is not a mission that fails. Crucially, the emptiness it rules out is emptiness with respect to God's own stated intentions — not the intentions of whoever quotes the verse.
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