Those who preach are to study the Word of God

Thus the chief and constant duty of the preacher is to conform unto that injunction,

“Study to show thyself approved unto God, a workman that needeth not to be ashamed, rightly dividing the word of truth” (2 Timothy 2:15).

In the whole of Scripture there is no exhortation addressed to preachers which is of greater importance than that one, and few equal. Doubtless that is why Satan has been so active in seeking to obscure its first two clauses by raising such a cloud of dust over the last one. The Greek word for “study” here signifies “give diligence”: spare no efforts, but make it your paramount concern and constant endeavor to please your Master. Seek not the smiles and flatteries of worms of the earth, but the approbation of the Lord. That is to take precedence of everything else: unless it is, attention to the second thing mentioned will be in vain. Entirely subordinate all other aims to commending thyself unto God — thine own heart and character, thy dealings with and walk before Him, ordering all thy ways according to His revealed will. What are your “service,” your ministrations, worth, if He be displeased with thee?

Arthur W. Pink-Interpretation of the Scriptures