An awkward construction, there being nothing to answer to καθὼς.
To abide (προσμεῖναι)
To continue on. The compound does not occur in Paul, but is found in Act 11:23; Act 13:43; Act 18:18.
When I went (πορευόμενος)
Better, was going, or was on my way. The participle cannot refer to Timothy.
Might'st charge (παραγγείλῃς)
See on Act 1:4. Very common in Luke and Acts, but not in Paul. In 1st Timothy alone five times.
Some (τισὶν)
Note the indefinite designation of the errorists, and comp. 1Ti 1:6; 1Ti 4:1; 1Ti 5:15, 1Ti 5:24; 1Ti 6:21. The expression is contemptuous. It is assumed that Timothy knows who they are. This is after the Pauline manner. See Gal 1:7; Gal 2:12; 1Co 4:18; 1Co 15:12; 2Co 3:1; Col 2:4, Col 2:8.
That they teach no other doctrine (μὴ ἑτεροδιδασκαλεῖν)
Better, not to teach a different doctrine. For ἕτερος different, see on Gal 1:6. The verb Pasto. olxx. oClass. The charge is not to teach anything contrary to the sound teaching (1Ti 1:10) or irreconcilable with it. Comp. Gal 1:6; 2Co 11:4; Rom 16:17.