What does it mean to be as wise as a serpent? When a serpent is attacked, it is willing to have much of its body severed, as long as it saves the head. So to be wise as a serpent means to be willing to lose everything - your wealth, your reputation, your friends - as long as you save your faith. Your faith is your head, by which you learn all truth; and by that truth your soul is set free. We should, however, recognize that the wisdom of the serpent is not enough; we must be honest and innocent as doves. Indeed it is the combination of wisdom and innocence that creates virtue. The person who is wise as a serpent can sustain the most terrible attacks and still continue to flourish as a disciple of Christ. The person who is innocent refuses to retaliate against those who make the attacks. To be as innocent as a dove means never to take revenge on those who wrong you or undermine you. Unless wisdom is tempered by innocence, one attack provokes another, and conflict continues without end. Unless innocence is tempered by wisdom, a person is so vulnerable that he will not even survive a single attack. Rest assured that no one can ever take away your faith; your wisdom guards against that. But be careful never to bear a grudge against anyone who does you wrong.
Of the teachings and proclamations preserved in the Church, some we possess from written teaching, while others we have received in secret from the Tradition of the Apostles; these both have the same validity [ie. authority] for true religion. And no one will deny these points, at least if he is even moderately experienced in Church [matters].
To be a righteous man among the righteous is a great and praiseworthy thing. But it is a far greater and more praiseworthy thing to be a righteous man among the unrighteous.
The Church Fathers regard Sacred Tradition as the safe guide in the interpretation of Holy Scripture and absolutely necessary for understanding the truths contained in the Holy Scripture. The Church received many traditions from the Apostles... The constitution of the church services, especially of the Divine Liturgy, the holy Mysteria themselves and the manner of performing them, certain prayers and other institutions of the Church go back to the Sacred Tradition of the Apostles.
Sacred Tradition is the very Church; without the Sacred Tradition the Church does not exist. Those who deny the Sacred Tradition deny the Church and the preaching of the Apostles. Before the writing of the Holy Scriptures, that is, of the sacred texts of the Gospels, the Acts and the Epistles of the Apostles, and before they were spread to the churches of the world, the Church was based on Sacred Tradition... The holy texts are in relation to Sacred Tradition what the part is to the whole.
They (namely the Apostles) have not handed down everything in writing, but have also delivered many things in unwritten form. The former and the latter are equally trustworthy, and so we also consider the [unwritten] Tradition of the Church to be trustworthy. Is it Tradition? Seek no further.