Jude 1:21Meaning & Commentary from the Church Fathers

And keep yourselves in the love of God, that is, preserve yourselves, awaiting mercy from the Lord, who on the last day will render to you eternal life.

That is, keep yourselves by receiving the mercy from the Lord, promised to you on the last day unto eternal life.

"Keep yourselves in love," and so forth: use every means and power to preserve God's love toward you and within you. See 1 Jn 5:18 and the note. Let the love of God be the abiding principle of your life and activity.

"Awaiting," with living hope (Rom 8:24), mercy, or the merciful and love-filled compassion toward human infirmities. Man needs this at every stage of his moral perfection (v. 2).

"Unto eternal life": prepared for the saints in the Kingdom of Heaven.

In conclusion (Jude 20-23), the holy Apostle Jude instructively sets forth the chief purpose of his epistle. It is that his readers, "building themselves up in their holy faith and praying in the Holy Spirit," should keep themselves in the love of God. They must also protect their neighbors by every means from heretical errors. "And on some have mercy." These are those infected by heretical deceptions through lack of understanding and through being carried away, not through an evil direction of the heart. Be merciful to them, but "with discernment," that is, learning the causes of their moral illness and taking appropriate measures for its healing.

Setting Christian life against the fleshly life of heretics, the apostle counsels Christians to live by the soul, building themselves up. This means grounding themselves in the principal rules of Christian faith and life. It also means constantly entrusting themselves to the guidance of the Spirit of God, especially in prayer. Through prayer Christian growth in faith, hope, and love is accomplished, and the great mercies of God are granted. These are so necessary for sinners on their path to the heavenly Kingdom. Since we often do not know for what or how we ought to pray, the apostle commands us to pray in the Holy Spirit, that is, with the help of the Holy Spirit (cf. Rom 8:26). We must ask for what is pleasing to Him, not for what is pleasing to our flesh, nor for what belongs to worldly vanity and leads neither us nor our neighbors to salvation.

Woe to the false teachers who have fallen away from the unity of faith and mock faith in the second coming of Christ. They have fallen away from the love of God, have been deprived of the grace of the Holy Spirit, and have lost hope of sharing in eternally blessed life. Warning against their deceptions, the Apostle Jude exhorts his beloved brethren in the faith to "build themselves up in the holy faith." That is, they must hold firmly to the holy faith, or the truth of Christ, which they have made their own by faith. This truth is the unshakable rock on which they may securely build their salvation (Mt 7:24). "Praying in the Holy Spirit" means praying with the gracious help of the Holy Spirit, drawn down by prayer performed in communion with the Holy Spirit.