Does the Aaronic and Melchisedec Priesthood Still Exist?

One of many peculiar doctrines taught by the LDS church is that the Aaronic and Melchizedek priesthoods still exist. In fact, they believe that Joseph Smith and Oliver Cowdery were ordained to the Aaronic Priesthood by John the Baptist in May, 1829.

Could it be that Psalms 110:4 (KJV) still applies? It reads, "The LORD hath sworn, and will not repent, Thou art a priest for ever after the order of Melchizedek."

But how could this be when the writer of the book of Hebrews says that Christ superseded both Aaronic and Melchisedecian orders. Hebrews 7:10 (KJV) reads, "For he (Moses) was yet in the loins of his father,  when Melchisedec met him."

Hebrews 7:11 and 12 (KJV) explains, "If therefore perfection were by the Levitical  priesthood, (for under it the people received the law,) what further  need was there that another priest should rise after the order of  Melchisedec, and not be called after the order of Aaron?"

Jesus made a new covenant with his disciples and all who would follow him afterward. As Hebrews 8:13 (KJV) declares, "In that he saith, 'A new covenant,' he hath made the first old. Now that which decayeth and waxeth old is ready to vanish away."

We who study the scriptures know how the curtain in the temple was torn from top to bottom, exposing the Holy of Holies and proclaiming that Aaronic priesthood ended. We also know that the temple and all Jerusalem was sacked by the Romans in A.D. 70 so that no more animal sacrifices could be performed there. As the writer of Hebrews pointed out in many places, Christ's sacrifice superseded the Aaronic priesthood and nullified it. Sadly, some folks, including faithful Mormons, still cling to these outmoded types and shadows.

This is why I feel compelled to write my next book called You Think You're Going to Heaven? People must know the difference between truth and lies or they'll end up in a cult. That's what happened to me and I want to save others from that fate.