John Chrysostom

And is then this Spirit within us? Yes, indeed, within us. For when we have driven away lying, and bitterness, and fornication, and uncleanness, and covetousness, from our souls, when we are become kind, tender-hearted, forgiving one another, when there is no jesting, when we have rendered ourselves worthy of it, what is there to hinder the Holy Spirit from coming and lighting upon us? And not only will He come unto us, but He will fill our hearts; and when we have so great a light kindled within us, then will the way of virtue be no longer difficult to attain, but will be easy and simple.