It is indifferences to the lost condition of unbelievers or to the carnal condition of other believers. The true character of a believer in Jesus Christ is determined by his mental attitude. See also 1 Pet. A Christian's mental attitude is not always apparent in his actions, but God always knows perfectly what a person is thinking. The following are examples of mental attitude thinking.
Worldliness is a mental attitude.
The remedy to the problem of worldliness is not in turning over a new leaf. Divine viewpoint must replace human viewpoint before a change in character can be expected. One can have an outward life which appears good, yet be filled with mental attitude sins. Toughness, strength, and determination are mental attitudes. One is not beaten until he gives up mentally.