Jude returns to the exhortative and brotherly tone of verses 1-3 to emphasize the importance of remembering (cf. 5) what the apostles proclaimed (cf. 1 Tim 4:1) and to oppose the ‘infiltrators’ who mock everything, sow discord, live immorally, and lack the Spirit—’ruah,’ the breath of God—that gives life (Gn 2:7). In this way, they live as if they are dead (17-19). For Jude, memory is essential to stay true to God’s plan.
In verses 20 and following, he sets aside his opponents. He speaks directly to the believers, his beloved, encouraging them to draw from the treasure chest of memories as their best tools for remaining committed to the Lord’s path. This includes faith, prayer, love, mercy, and compassion for doubters, though with caution not to become contaminated (cf. Rev 18:4). It is important to note that, despite the author’s strong stance against the ‘infiltrators,’ he urges the community to show compassion toward them (22ff), but with great caution.