Albert Barnes Commentary Jude 1:21

"keep yourselves in the love of God, looking for the mercy of our Lord Jesus Christ unto eternal life." — Jude 1:21 (ASV)

Keep yourselves in the love of God. This phrase still refers to their own agency. Regarding the duty commanded here, see Barnes on John 15:9.

The phrase "the love of God" may mean either God's love to us, or our love to him. The latter meaning, however, appears to be the sense here, because the duty to maintain God's love to us is not one that could be commanded. That is a point over which we can have no control, except insofar as it may result from our obedience. However, we can be commanded to love him, and to keep ourselves in that love.

Looking for the mercy of our Lord Jesus Christ. This refers particularly to when he will come to receive his people to himself (see Barnes on Titus 2:13; see Barnes on 2 Peter 3:12; see Barnes on 2 Timothy 4:8).