Don't ask me about G777 sinless spirit doctrine, Stephen.. I don't get it either.
I believe "perfect" or telios means spiritual mature in Christ which means having sound doctrine, showing fruit of walking with His Spirit and heavenly wisdom, humbleness and agape love.
I don't even pretend to speak for G777 but will make the following statements....
a. Our birth is spiritual (born again of the spirit)
b. Our spiritul birth is of incorruptable SEED (cannot be corrupted, beyond the abilty to be corrupted)
c. Our spiritual birth results in the SEAL of God (by the Holy Spirit)
d. That seal stands sure in the fact that God KNOWS all who are his (THE seal identifies us as belonging to God)
e. It is the SPIRIT that we have that has been BORN of GOD and does NOT SIN because it is (incorruptable) <-John
Jesus speaks to this when he speaks to his saved, immersed disciples that is identifed as a church atleast twice in te preent tense when he states, "The spirit is indeed willing, but the flesh is weak"
God's kingdom is SPIRITUAL, GOD is SPIRIT, OUR BIRTH is spiritual and the flesh profits nothing.....the body is dead because of sin, not subject unto the word of God, neither indeed can be.....however...the SPIRIT that is born of incorruptable seed always seeks to do right, is sinless and eternally secure in Christ......Jesus, John and Paul all cover this...though rejected, denied and swept under the rug by many.....especially those who teach salvation can be lost or gained and kept by works.............