How does regular bible reading and in depth study benefit the reader (especially pastors)? Charles Bridges says:
It fills the mind with the most splendid form of heavenly truth, which it teaches with purity, solidity, certainty, and without the least mixture of error. It soothes the mind with an inexpressible sweetness; it satisfies the sacred hunger and thirst for knowledge with flowing rivers of honey and butter; it penetrates into the innermost heart with irresistible influence; it imprints its own testimony so firmly on the mind, that the believing soul rests upon it with the same security, as if it had been carried up into the third heaven, and heard it from God's own mouth; it touches all the affections, and breathes the sweetest fragrance of holiness upon the pious reader, even though he may not perhaps comprehend the full extent of his reading. (emphasis added)
Taken from the kindle edition of The Christian Ministry by Charles Bridges sixth edition ©1844. Published by Seeley, Burnside, and Seeley.