Imitation of Christ

Multum et diu oportet hominem in se ipso certare, antequam discat se ipsum plene superare, et totum affectum suum plene in Deum trahere. Quando homo stat super se ipsum, facile labitur ad consolationes humanas. Sed verus Christi amator, et studiosus sectator virtutum non cadit super illas consolationes, nec quærit tales sensibiles dulcedines. Sed magis fortes tentationes et exercitationes, et pro Christo duros sustinere labores. 

Mightily and long must a man strive within himself before he learns altogether to overcome himself, and to draw his whole affection towards God. When a man rests upon himself, he easily slips away to human comforts. But a true lover of Christ, and a diligent seeker after virtue, doesn't fall back upon those comforts, nor seeks such sweetness as may be tasted and handled, but desires rather hard exercises, and to undertake severe labours for Christ.

Imitation of Christ, II, 9:3