‘Of the Jews five times I received forty stripes save one. Thrice was I beaten with rods, once was I stoned, thrice I suffered shipwreck, a night and a day have I been in the deep, in journeyings often, in perils of rivers, in perils of robbers, in perils from my countrymen, in perils from the Gentiles, in perils in the city, in perils in the wilderness, in perils in the sea, in perils among false brethren; in labour and travail, in watchings often, in hunger and thirst, in fastings often, in cold and nakedness.'
He outlines his credentials. By the very Jews whom they boast that they are one with, he has five times received the maximum beating allowed, forty stripes less one (compare Deuteronomy 25:2-3). He has been beaten with Roman rods three times by the lictors (rod-bearers - Acts 16:22). Strictly as a Roman citizen he was exempt from such treatment but the law was as regularly abused as used. Some observed it, others ignored it as both Cicero and Josephus bring out.
He has been stoned. This would be by Jews, it was a Jewish form of punishment for blasphemy. See Acts 14:5; Acts 14:19. He has been shipwrecked three times. Regular travellers at sea, especially in smaller boats, were often subject to shipwreck due to sudden storms. On one such occasion he spent a night and a day keeping himself afloat in the sea (or in a small boat similar to a lifeboat) before being rescued. He has faced every form of difficulty and danger that regularly faced travellers who went unescorted. Arduous journeys. Perilous river crossings. Danger from robbers. Threats, whether from his own countrymen, or from Gentiles. He has been imperilled in all types of surroundings, whether in cities or in the countryside, or in the desert, or in the sea, or among ‘pseudo-brethren', some who like his opponents in Corinth sought to destroy him. He has laboured and had to struggle hard, he has often had to stay awake at night because of threats all around, he has been hungry and thirsty, he has gone without food often, he has been bitterly cold and insufficiently clothed, often in rags. (How are his opponents doing in comparison with this in the service of Christ?)