A.T. Robertson Commentary 1 Timothy 1:3

"As I exhorted thee to tarry at Ephesus, when I was going into Macedonia, that thou mightest charge certain men not to teach a different doctrine," — 1 Timothy 1:3 (ASV)

As I exhorted (καθως παρεκαλεσα). There is an ellipse of the principal clause in verse 4 (so do I now not being in the Greek).

To tarry (προσμεινα). First aorist active infinitive of προσμενω, old verb, attributed by Luke to Paul in Ac 13:43.

That thou mightest charge (ινα παραγγειληις). Subfinal clause with ινα and the first aorist active subjunctive of παραγγελλω, old verb, to transmit a message along (παρα) from one to another. See 2 Thessalonians 3:4,6,10. Lock considers this idiom here an elliptical imperative like Eph 4:29; 5:33.

Certain men (τισιν). Dative case. Expressly vague (no names as in 1:20), though Paul doubtless has certain persons in Ephesus in mind.

Not to teach a different doctrine (μη ετεροδιδασκαλειν). Earliest known use of this compound like κακοδιδασκαλειν of Clement of Rome. Only other N.T. example in 6:3. Eusebius has ετεροδιδασκαλος. Same idea in Ga 1:6; 2 Corinthians 11:4; Romans 16:17. Perhaps coined by Paul.