Words from God

Isaiah 55:10-11
    “For as the rain comes down, and the snow from heave,
    And do not return there,
    But water the earth
    And make it bring forth and bud,
    That it may give seed to the sower
    And bread to the eater,
    So shall My word be that goes forth from My mouth;
    It shall not return to Me void,
    But it shall accomplish what I please,
    And it shall prosper in the thing for which I sent it.” NKJV

    I’ve often heard this verse quoted but not known the context. “His word shall not return void,” I’m told, often to justify random teachings or street evangelisms. It seemed strange to me because that would also seem to justify TOB (turn or burn) sermons. After all, they use His word (hopefully).
    Out of context, it would also seem to imply that going around and posting random bible verses would be guaranteed to have an impact. But the sentence before doesn’t say that.
    “So shall My word be that goes forth from My mouth.”
    “…From My mouth.”
    That, to me, implies a need for these things to be from God, and due to the work of His Spirit.
    Application:
    When I preach/teach/talk about His word, I need to make sure it is something from Him and not form me.