One that ruleth well his own house, having his children in subjection with all gravity;
Ruleth, х proistamenon (G4291)] - 'presiding over.' His own house - children and servants, as contrasted with 'the church (house) of God' (1 Timothy 3:5; 1 Timothy 3:15), which he is to preside over.
Having his (Greek has no his) children (Titus 1:6).
Gravity - reverent propriety. His having children in subjection to him in all gravity is a recommendation to him as one likely to rule well the church.