Albert Barnes on 1 John 4:17

Herein is our love made perfect. Marg., love with us. The margin accords with the Greek--μεθημων. 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 in which the apostle specifies. In this way love becomes what it should be, and will prepare us to appear with confidence before the judgment-seat. Comp. 1Jn 4:12.

That we may have boldness in the day of judgment. By the influence of love in delivering us from the fear of the wrath to come, 1Jn 4:18. The idea is, that he who has true love to God will have nothing to fear in the day of judgment, and may even approach the awful tribunal where he is to receive the sentence which shall 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 which the Saviour had, and, resembling him, we need not be alarmed at the prospect of meeting him.

(1) "Herein is our love" "love with us"