All human titles are only shadows of God's authority from which they derive, Ephesians 3:15. RE: "call no one on earth Abi father". "Father" is a term sometimes used of the great Rabbis. Note our Lord is not a grammarian regulating the use of terms: he is a doctor of the spirit. He forbids any acknowledgement of fatherhood that obscures the fatherhood of God, nothing more. If we make no allowance for the concreteness and brevity of his phrases we reduce either them to absurdity or him to inconsistency. He would not forbid a human son to use the word father nor would he forbid the term if addressed to one who is God's representative; in this second case, indeed, it serves to remind its user of the fatherhood of God. Nor must the Christian disciple pose as an independent spiritual guide. He himself is subject to one Teacher and one Guide - to the Lord Himself.