Luke 5:5

‘And Simon answered and said, “Master, we toiled all night, and took nothing: but at (on the strength of) your word I will let down the nets.” '

He gives the hint to Jesus that it is really a waste of time. As experienced fishermen they have tried and failed, nevertheless if He really wants them to, he will do it. ‘Master, we have been fishing all night, and it has been hard toil, and I am very tired, and we have caught nothing, but if you tell me to, then I will do what you say. I will again throw out the nets.' It was the response of a godly man to a revered teacher. He politely refrained from pointing out that one just did not fish at that time of day with the hope of catching anything substantial.

‘Master' is a favourite word of Luke for when the disciples address Jesus. He sees it as the best word to use for his Greek readers to explain ‘Rabbi' and ‘Teacher', although he uses ‘Teacher' when Jesus is being addressed by non-disciples.

Note the use of ‘word'. Peter recognised that hopeless as it might be this was a prophetic word that he must obey.