Paul is telling Timothy to command those who are teaching false doctrine to stop the fables and the endless genealogies. They do not edify. The purpose or the goal is to have a pure heart, faith, and a good conscience before God. That is what God wants from us. Paul wants Timothy to expand his horizons'to stop and think of what God wants from him. In verses 6-7, we can see quite a few did not do this.
John O. Reid (1930-2016)
Don't Take God for Granted
Studying a specific theological subject for months and years will make a person unbalanced, emotionally attached to the topic, and deficient in the weightier matters of God's way of life. Such persons become gluttons for new ideas that feed heresy, and they justify their over-consumption by claiming that it is not their fault that they have access to so much religious information over the Internet and through the mail.
"Much study"—especially of a trivial subject or one unrelated to salvation—"is wearisome to the flesh," writes Solomon (Ecclesiastes 12:12). People of this inclination, the apostle Paul says, are "always learning and never able to come to the knowledge of the truth" (II Timothy 3:7). Just as with food, excessive study of the same subject day-in and day-out can cause a person to be unbalanced. We have to know when to say, "Enough!"
Martin G. Collins
Gluttony: A Lack of Self-Control (Part Two)
Other Forerunner Commentary entries containing 1 Timothy 1:5: