Passage
See how great a love the Father has given to us, that we would be called children of God; and we are. For this reason the world does not know us, because it did not know Him.
1 John 3:1 (LSB)
Nearby Context
1 John 3:1 See how great a love the Father has given to us, that we would be called children of God; and we are. For this reason the world does not know us, because it did not know Him.
1 John 3:2 Beloved, now we are children of God, and it has not been manifested as yet what we will be. We know that when He is manifested, we will be like Him, because we will see Him just as He is.
1 John 3:3 And everyone who has this hope fixed on Him purifies himself, just as He is pure.
Study Lenses
The verse centers on "called", "world", "great", "love", "father", "given", "children", and "reason". It is saying that the verse draws attention to "called" and "world", so its meaning should be read from those terms before moving to application.
The next verse adds "Beloved now we are children of God...", so "called" and "world" should be read forward into that movement. In 1 John context, the local focus is Christ, faith, and discipleship.
A plain takeaway is to answer the verse's own emphasis on "called" and "world" with trust shaped by these words, not by a vague optimism outside the passage.