A.T. Robertson Commentary 3 John 1:2

"Beloved, I pray that in all things thou mayest prosper and be in health, even as thy soul prospereth." — 3 John 1:2 (ASV)

I pray (ευχομα). Here only in John's writings. See Ro 9:3.

In all things (περ παντων). To be taken with ευοδουσθα and like περ in 1 Corinthians 16:1, "concerning all things."

Thou mayest prosper (σε ευοδουσθα). Infinitive in indirect discourse (object infinitive) after ευχομα, with accusative of general reference σε (as to thee). Ευοδοω is old verb (from ευοδος, ευ and οδος, prosperous in a journey), to have a good journey, to prosper, in LXX, in N.T. only this verse (twice), 1 Corinthians 16:2; Romans 1:10.

Be in health (υγιαινειν). In Paul this word always means sound teaching (1 Timothy 1:10; 1 Timothy 6:3), but here and in Lu 5:31; 7:10; 15:27, of bodily health. Brooke wonders if Gaius' health had caused his friends anxiety.

Even as thy soul prospereth (καθως ευοδουτα σου η ψυχη). A remarkable comparison which assumes the welfare (present middle indicative of ευοδοω) of his soul (ψυχη here as the principle of the higher life as in Joh 12:27, not of the natural life as in Mt 6:25).