Origen

This we may understand not of the material elements of the world; but here the men who are in the world, are called the worlda. But Christ’s disciples are not of this world, whence there cannot be woe to them from offences; for though there be many offences, they do not touch him who is not of this world. But if he be yet of this world in loving the world, and the things in it, as many offences will seize him as those by which he was encompassed in the world. It follows, For it must needs be that offences come.