The expected outcome of sowing the gospel is Mark 4:32

But when it is sown, it grows up, and becomes greater than all herbs, and shoots out great branches; so that the fowls of the air may lodge under the shadow of it.

The seed sowing does not always result in the productivity of Mark 4:32. At least we are aware that several outcomes are possible. God – or his agents – do not have a lock on where the seed lands. The certainty of Mark 4:32 rests with God’s accuracy and irresistible will.

God does not prepare every patch for the seed