Jesus Christ is the same yesterday, today and forever. (NIV)
1. There is nothing in the context to warrant believing that this verse has anything to do with a “plurality of persons,” “one substance in the Godhead” or any other Trinitarian concept. The verses around verse 8 tell believers not to be fooled by strange new doctrines. The verse preceding it says to “remember” the leaders and “imitate” them. The verse just it after says, “Do not be carried away by all kinds of strange teachings.” The context makes the intent of the verse obvious. Believers were being led astray by new teachings, and the author of Hebrews was reminding them that Jesus Christ does not change. The truth about him yesterday is the same now and will be the same in the future.
2. Although some people try to use this verse as if it said that Jesus Christ has existed from eternity past, the very wording shows that is not the case. A study of the word “yesterday” in Scripture shows that it refers to something that happened only a short time before. It stretches the grammar beyond acceptable limits to try to make this verse say that Christ has always existed.
3. It has been widely recognized by theologians of many backgrounds that this verse is referring to the fact that Christian truth does not change. Morgridge writes: “This passage refers not to the nature, but to the doctrine of Christ. With this exposition agree Adam and Samuel Clark, Calvin, Newcome, Whitby, Le Clerk, and the majority of expositors.”
Morgridge, p. 123
Norton, p. 269