The Holy Spirit inspired the writers of the New Testament in Greek not Aramaic. The words used in Matthew 16:18 are NOT Kepha and kepha. The words used in the only manuscripts available are Petros and petra. Each has a distinctly different meaning.
From Stong's:
4074 Pétros (a masculine noun) – properly, a stone (pebble), such as a small rock found along a pathway.
4073 pétra (a feminine noun) – "a mass of connected rock," which is distinct from 4074 (Pétros) which is "a detached stone or boulder" (A-S). 4073 (pétra) is a "solid or native rock, rising up through the earth" (Souter) – a huge mass of rock (a boulder), such as a projecting cliff.
>>What Jesus said to Simon in Matthew 16:18 was this: ‘You are Kepha, and on this kepha I will build my Church.<<
Not according to what the Holy Spirit had written.
What metmom posted was correct. Until you can prove that the Holy Spirit originally had Mathew written in Aramaic your claim is totally in error.