Albert Barnes Commentary 1 John 4:17

"Herein is love made perfect with us, that we may have boldness in the day of judgment; because as he is, even so are we in this world." — 1 John 4:17 (ASV)

Herein is our love made perfect. The marginal reading is love with us. The margin agrees with the Greek—mey hmwn. The meaning is, "the love that is within us, or in us, is made perfect." The expression is unusual; but the general idea is that love is rendered complete or entire in the manner the apostle specifies. In this way, love becomes what it should be and will prepare us to appear with confidence before the judgment seat. (Compare to 1 John 4:12).

That we may have boldness in the day of judgment. This boldness comes through the influence of love, which delivers us from the fear of the wrath to come (1 John 4:18). The idea is that he who has true love for God will have nothing to fear on the day of judgment and may even approach the awe-inspiring tribunal, where he is to receive the sentence that will determine his everlasting destiny, without alarm.

Because as he is, so are we in this world. That is, we have the same traits of character that the Saviour had, and, resembling him, we need not be alarmed at the prospect of meeting him.