That term means that He is the sole representative of the Being and character of the One who sent Him. Begotten does not suggest a commencement of beginning, though it does speak of a relationship. It is a fact that is irrespective of time. There are things that are true of Him that cannot be completely so of the people that live upon this earth.
Imperfection is stamped upon every human being.
Our humanness is so often manifested in our daily living. There are no flaws or imperfections to be found in Him. The offerings of the Old Testament had to be repeated year after year. There was no permanent efficacy in the blood of bulls, goats, birds or other animals. The shedding of the imperfect animal blood merely pointed ahead to the perfect, atoning blood of the Son of God, the Lord Jesus Christ.