en_tn/2jn/01/07.md

many deceivers

This could be translated "many false teachers" or "many imposters"

for many deceivers have gone out into the world

This could be translated "many false teachers have left the congregation."

Jesus Christ came in the flesh

This is a metonymy that means "Jesus Christ came as a real human" (See: rc://en/ta/man/translate/figs-metonymy)

This is the deceiver and the antichrist"

This could be translated "they are the ones who deceive others and oppose Christ himself"

Look to yourselves

"Watch out" or "Pay attention"

lose the thing

This could be translated "lose your future rewards in heaven"

full reward

This could be translated "complete reward in heaven"