When he told them what to do, they obeyed and that is when blessing comes, when we obey. We have to remember that all the great blessings of the Bible come from obedience, and God wants us to note his details and to take them seriously.
We are reminded that we must never think that the preacher can do everything by himself. We are all in this work together, preacher and congregation: the Lord insists on it. You get an insight into working together as a team. This is how the Lord has organised local churches, we work together as a team and we organise together in gospel work.
The results often come in an unpredicted manner, not in the way that we expect. What the Lord Jesus Christ told these disciples to do was the last thing they would have done. Their experience told them that if you had a bad night you might as well pack up because the morning was no time to fish, and their energy and their strength were exhausted. But God proves to us that the blessing is of him. We will do all we can and sometimes we will visit a neighbourhood and we will struggle and strive, and then all of a sudden a fresh crop of souls will come in through some other quite different department of the work. God does bless the efforts of his people and he is with us, but often the blessing will come in some other way, and yet, we believe, on account of what we are doing. Chiefly we learn that all our efforts and all our labour is useless without the mighty blessing of God. We must be striving and working for the Lord, but all our striving is unblessed unless the Spirit of God moves.