Our words are hit and miss. We make promises, but we can not guarantee anything absolutely. We try to find words to encourage and heal and they occasionally fall flat. Yet the word of God is seen as a force in itself. Isaiah speaks of the ower of the Word in this passage. John calls Christ the Word in his introduction tot he Gospel. The Word of God spoken will be fruitful, the Word of God Incarnate, even more so.
As the rain and the snow
come down from heaven,
and do not return to it
without watering the earth
and making it bud and flourish,
so that it yields seed for the sower and bread for the eater,
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.
In the beginning was the Word,
and the Word was with God,
and the Word was God.
He was with God in the beginning.
Through him all things were made;
without him nothing was made that has been made.
In him was life,
and that life was the light of all mankind.