‘For he was amazed, and all who were with him, at the draught of the fishes which they had taken, and so also were James and John, sons of Zebedee, who were partners with Simon.'
Luke then explains the reason for Peter's words. It was because he, and all who were with him, together with their partners James and John in the other boat, were filled with astonishment at this amazing happening. They all had many years of fishing experience behind them, but they had never seen anything like this. (The reversion to ‘Simon' adds emphasis to the inclusion of Peter in the previous verse).
We note all through how skilfully Luke keeps the attention on Simon Peter, while bringing in others when necessary, and cleverly introducing James and John so that they can be involved in the call, and yet without taking the attention off Simon Peter.