That he did not possess immortality before his resurrection by God is seen from the inspired apostle’s words at Roman 6:9 when it says, "Christ, now that he has been raised up from the dead, dies no more; death is master over him no more," and Revelation 1:17, 18 confirms this when it says,
"When I saw him, I fell as dead at his feet. And he laid his right hand on me and said: “Do not be afraid. I am the First and the Last, and the living one, and I became dead, but look! I am living forever and ever, and I have the keys of death and of the Grave.
For this reason, when describing Jesus as “the King of those who rule as kings and Lord of those who rule as lords,” 1 Timothy 6:15, 16 shows that Jesus is distinct from all such other kings and lords in that he is “the one alone having immortality.” The other kings and lords, because of being mortal, die, even as did also the high priests of Israel. The glorified Jesus, God’s appointed High Priest after the order of Melchizedek, however, has “an indestructible life.” (Hebrews 7:15-17, 23-25)