The answer
In Holy Gospel of St. John 21:7 "Now when Simon Peter heard that it was the Lord, he put on his outer garment (for he had removed it) and plunged into the sea."It should be noted that Simon Peter put on his garment in preparation for to jumping into the water. He had taken his clothes, outer garment, off to start fishing. St. Peter was not prepared to meet the Lord Jesus Christ as he had taken his outer garment off. He had to prepare himself to meet the Lord. Please note that in the beginning, St. John recognized the Lord, and not St. Peter. He was NOT ready to greet the Lord. It is very hard for those who are UNREADY for the Lord, to know Him.
It should also be noted that the Jews at that time considered a greeting as a religious act that could be done only with the clothes on.
Answered by His Eminence Metropolitan Youssef (opens in a new tab)