"Routinization of the religious and ethical life comes to expression not only in thoughtlessness and weakness but also as a defense against God's true and living demands. Indeed, behind a fanatic zeal for God there may lie obduracy and hatred. An intense ethical program may be pursued at the same time as the heart is hardened and rebellious." (61)
"The opposite of the 'love' which is the ideal attitude in life (Deut. 6:5)...is egoism: withholding one's 'heart' from God and other people, regarding life as one's own possession, grabbing for oneself instead of giving to others." (139)
"Behind the façade and the routines, the center of the personality may very well remain unengaged, free to pursue its own interests. The heart is still closed to God; he is not permitted to rouse a living love or to inspire living deeds." (139-140)
Quotations from: Birger Gerhardsson. The Ethos of the Bible. Translated by Stephen Westerholm. Philadelphia: Fortress Press, 1981.
(It's an oldie, but a goodie: an exposition of the ethos of Matthew, Paul and the Johannine literature, with a focus on the role of the Shema in shaping early Christian ethics. Well worth reading if you can find a copy--and apparently still available, thanks to a Wipf&Stock reprinting.)