RESPONSE:
I’m curious why you would want a copy of Matt 16:18 in Aramaic. Peter’s Confession of Faith in Matthew 16 was copied from the earlier Mark (also written in koine Greek) pretty much verbatim. But at some point the Matt 16:18 et seq was added, probably after it was realized that Jesus’ second coming wasn’t imminent and a new church was founded.
Mark 8:27-30 “Now Jesus and his disciples set out for the villages of Caesarea Philippi. Along the way he asked his disciples, “Who do people say that I am?” They said in reply, “John the Baptist, others Elijah, still others one of the prophets.” And he asked them, “But who do you say that I am?” Peter said to him in reply, “You are the Messiah.” Then he warned them not to tell anyone about him.” (NAB)
Matt16:13-20 “Then Jesus went into the region of Caesarea Philippi he asked his disciples, “Who do people say that the Son of Man is?” They replied, “Some say John the Baptist, others Elijah, still others Jeremiah or one of the prophets.” He said to them, “But who do you say that I am?” Simon Peter said in reply, “You are the Messiah, **the Son of the living God.” Jesus said to him in reply, “Blessed are you, Simon son of Jonah. For flesh and blood as not revealed this to you, but my heavenly Father. And so I say to you, you are Peter, and upon this rock I will build my church, and the gates of the netherworld shall not prevail against it. I will give you the keys to the kingdom of heaven. Whatever you bind on earth shall be bound in heaven; and whatever you loose on earth shall be loosed in heaven.” ** Then he strictly ordered his disciples to tell no one that he was the Messiah.” (NEB)
The part in bold type appears to be the later insertion into Mark’s original.