-
The way I see his statement; Paul is juxtaposing mortality with immortality. In other words; Christ died mortal but was raised from the dead immortal.
†. Rom 6:9 . . For we know that since Christ was raised from the dead, he cannot die again; death no longer has mastery over him.
When Christ's believing followers die, they too die mortal, but like him, they too will be raised from the dead immortal.
†. 1Cor 15:52-53 . . In a moment, in the twinkling of an eye, at the last trumpet; for the trumpet will sound, and the dead will be raised imperishable, and we shall be changed. For this perishable must put on the imperishable, and this mortal must put on immortality.
But that's neither here nor there because this thread isn't about immortality; it's about eternal life; which, according to John 5:26 and 1John 1:1-2, Christ already had before he died.
================================