During his fourth missionary journey, Paul had instructed Timothy to care for the church at Ephesus while he went on to Macedonia. When he realized that he might not return to Ephesus in the near future, he wrote this first letter to Timothy to develop the charge he had given his young assistant. This is the first of the “Pastoral Epistles.”
The design of the epistle appears to be, that Timothy having been left at Ephesus, St. Paul wrote to instruct him in the choice of proper officers in the church, as well as in the exercise of a regular ministry. Also, to caution against the influence of false teachers, who by subtle distinctions and endless disputes, corrupted the purity and simplicity of the gospel. He presses upon him constant regard to the greatest diligence, faithfulness, and zeal. These subjects occupy the first four chapters; the fifth chapter instructs respecting particular classes; in the latter part, controversies and disputes are condemned, the love of money blamed, and the rich exhorted to good works.
Matthew Henry