That each one of you know how (eidenai ekaston umwn). Further epexegetic infinitive (second perfect active), learn how and so know how (learn the habit of purity). To possess himself of his own vessel (to eautou skeuo ktasqai). Present middle infinitive of ktaomai, to acquire, not kekthsqai, to possess. But what does Paul mean by "his own vessel"? It can only mean his own body or his own wife. Objections are raised against either view, but perhaps he means that the man shall acquire his own wife "in sanctification and honour," words that elevate the wife and make it plain that Paul demands sexual purity on the part of men (married as well as unmarried). There is no double standard here. When the husband comes to the marriage bed, he should come as a chaste man to a chaste wife.