Basil the Great
Catena Aurea · Lukasevangelium 10
And, behold, a certain Lawyer stood up, and tempted him, saying, Master, what shall I do to inherit eternal life? He said unto him, What is written in the law? how readest thou? And he answering said, Thou shalt love the Lord thy God with all thy heart, and with all thy soul, and with all thy strength, and with all thy mind; and thy neighbour as thyself. And he said unto him, Thou hast answered right: this do, and thou shalt live.
(in Ps. 44.) By saying, with all thy mind, he does not admit of any division of love to other things, for whatever love you cast on lower things necessarily takes away from the whole. For as a vessel full of liquid, whatever flows therefrom must so much diminish its fulness; so also the soul, whatever love it has wasted upon things unlawful, has so much lessened its love to God.