Lay hands hastily on no one, neither be a participant in other men's sins. Keep yourself pure.
Keep thyself pure I consider this also to have the same reference as the preceding clause. As if he had said, “If others do anything that is wrong, beware lest any contagion reach you, either by consent or by approbation. If you cannot hinder them from polluting themselves, it is at least your duty to have your counsels at all times separated from theirs, so that you may keep yourself pure.” If any prefer to view it as a general statement, let him enjoy his opinion; but, for my own part, I reckon it to be more suitable to limit it to the present context. 