Does the Word return void? (Proper A10)

Does Jesus' parable in Matthew contradict the prophet saying

"so is my word that goes out from my mouth:
It will not return to me empty,
but will accomplish what I desire
and achieve the purpose for which I sent it."?

Jesus indicates that the word broadcast in the field doesn't always bring forth the intended results everywhere.

Isaiah speaks not of the preaching or proclamation of the word of God, but the promises themselves. The promise of the Gospel is not negated; rather the extravagant farmer sows even where there is little chance of a harvest.

Is it the sovereignty of God that makes some ground unreceptive, or is it simply a fact? Can Jesus' parable be taken as a promise that at least some seed sown will grow? If so does that mean that every time the word is read it will take root somewhere in our lives, or at least in somebody in the congregation? Or do we have to bring our attention to the word for it to be planted well?

As Ray Orth asked today, "Where is the Gospel in this text? With out it your churches will wither and die! What is the seed?" The Word of God - the creative voice of God, his very work in salvation-history, the act of Christ upon the cross and the resurrection itself. These are pregnant seeds! Think of all the power of the voice of God packed into these tiny packets and spread abroad in our hearts. This is a beautiful image.

Taken within the context of the week, the focus of the text is the Word of God and its power in our lives. Where can it flourish? What power does it have when it begins to grow? Even the tiny seed will transform us if we attend to it with a fertile soil.