2 — For the sake of the truth which abides in us and will be with us forever.
Neither the Word of God, which we have received, nor the Savior and Lord, who inspired it and lives in us, will ever change or abandon us (Heb. 13:8). God’s truth does not alter from age to age, nor does He.
5 — I ask you, lady, not as though I were writing to you a new commandment, but the one which we have had from the beginning, that we love one another.
The core commandment of heaven—to love God and love others as we love ourselves—has remained the same from Old Testament times (Lev. 19:18; Deut. 6:5; 10:12), to the days of the New Testament (Matt. 22:36–40; John 13:34, 35; 15:9–17), and on to today.
8 — Watch yourselves, that you do not lose what we have accomplished, but that you may receive a full reward.
God desires to fully bless us by giving us the maximum number and quality of rewards possible—but we determine what kind of reward we will receive based on how closely we walk with Him and thereby obey His voice.