Clement of Alexandria

And by following the divine scripture, the path by which believers travel, we are to be made like unto the Lord as far as possible. We must not live as if there were no difference between right and wrong, but, to the best of our power, must purify ourselves from indulgence and lust and take care for our soul which must continually be devoted to the Deity alone. For when it is pure and set free from all evil the mind is somehow capable of receiving the power of God and the divine image is set up in it. "And everyone who has this hope in the Lord purifies himself," says the Scripture, "even as he is pure." To attain the knowledge of God is impossible for those who are still under the control of their passions. Therefore they cannot attain the salvation they hope for as they have not obtained any knowledge of God.