15. Moreover, we are found also to be edei sheker (false witnesses) [SHEMOT 20:16; DEVARIM 19:16-21] misrepresenting Hashem Himself, because we gave solemn edut (testimony 1:6) as in the presence of G-d that Hashem raised Rebbe, Melech HaMoshiach--whom, of course, He did not raise if, as you say, the Mesim are not bemetzius (in fact) raised.
16. For if the Mesim (Dead persons) have not Techiyah, neither has Rebbe, Melech HaMoshiach had a Techiyah;
17. And if Rebbe, Melech HaMoshiach has not already had his Techiyah from the Mesim, your emunah is futile, you are still in your averos (sins),
18. And even the ones who sleep the sleep of the Mesim in Rebbe, Melech HaMoshiach have perished.