Passion-free knowledge of divine things does not persuade the intellect to scorn material things completely; it is like the passion-free thought of a sensible thing. It is therefore possible to find many men who have much knowledge and yet wallow in the passions of the flesh like pigs in the mire. Through their diligence they temporarily cleanse themselves and attain knowledge, but then they grow negligent. In this they resemble Saul: for Saul was granted the kingdom, but conducted himself unworthily and was driven out with terrible wrath (cf. 1 Sam. 10-15).

St Maximos the Confessor, Four Hundred Texts on Love