en_tn/1jn/05/20.md

we know

"We" refers to all believers.

given us understanding

"Has enabled us to understand the truth." (UDB)

we know him who is true,

"him" refers to God the Father.

we are in him

See how this was translated in 1 John 2:4.

Dear children

See how you translated this in 1 John 2:1.