13:8

Jesus Christ is the same yesterday and today, and forever: Paul here assures his readers that Jesus’ qualities, teachings, and personality will never change. In the preceding verse, he urged his fellow believers to imitate the faith of those taking the lead in the Christian congregation. However, even those faithful and exemplary elders would eventually die. Jesus, in contrast, lives forever and will remain the same. So he will always be the foremost One whom Christians should imitate. Paul’s readers had every reason to cling to and rely on what Jesus taught. Even if everything in a Christian’s life were to change, he could always rest his faith on Jesus. (Heb 12:2) So Christians could put their full trust and confidence in their Leader and the head of the congregation. (Mt 23:10; Col 1:18; 1Pe 2:21) Further, the message Jesus preached is called “everlasting good news”; it will always be relevant and beneficial. (Re 14:6) Because Jesus is so constant and reliable, his followers have good reason to heed Paul’s next exhortation not to be “led astray by various and strange teachings.”​—Heb 13:9.

yesterday and today: The phrase “yesterday and today” was used in the Hebrew Scriptures to express continuity. (Ex 5:14) In mentioning “yesterday,” Paul may have had in mind Jesus’ prehuman life as well as his earthly ministry. From the time that humans were created, God’s Son had always shown tender care for them as well as unwavering adherence to his Father and his Father’s teachings. (Pr 8:30, 31; Joh 1:14; 7:16, 17; 17:5; Php 2:5-8; Col 1:15; Heb 1:3; 2:3; 5:7) By using the expression “today,” Paul shows that Jesus, as “head of the congregation,” has continued to display the same attitude and qualities.​—Eph 5:23; Col 1:18.

forever: Several times in this letter, Paul uses this word in connection with Jesus. For example, he says that Jesus is “a priest forever in the manner of Melchizedek” (Heb 5:6; compare Heb 6:20), that Jesus “continues alive forever” (Heb 7:24), and that he “has been made perfect forever” (Heb 7:28). Such expressions powerfully demonstrate the superiority of the Christian way of worship, since it centers on an eternal High Priest and King.