Therefore, brethren, stand fast, and hold the traditions which ye have been taught, whether by word, or by our letter. - 2 Thessalonians 2:15

Guarding our Faith against Ecumenism & Modernism
Ecumenism is a real and existential threat to our faith. It is real - as opposed to merely theoretical or imagined, because of the many 'progress' Ecumenists have made in the last century towards union with the Heterodox without the heterodox accepting the fullness of the Orthodox Faith and renouncing their errors. The threat is also most importantly existential because while Christ says the 'gates of hell will not prevail' against the Church, this does not by extension mean all jurisdictions or parishes are somehow 'safe' inspite of their provocations against Holy Tradition. Indeed the fall of the once Orthodox Rome is cautionary proof that even Orthodox Patriarchates may fall away from the faith once they begin to depart from the Apostolic Faith and go after human innovations. Consider the words of Christ himself when he asks - 'when the Son of man cometh, shall he find the faith on the earth?' - Lk 18:8 as being especially directed to us who live closer to that day than any generation of Orthodox Christians before us. Therefore as the Apostles say in scripture 'keep the traditions' [2 Thes 2:15] ; 'hold the traditions' [1 Cor 11:2]; the word used is traditions - it is not speaking only of dogmas; but the word 'παράδοσις' encompasses all that has been handed down.

Remember: The Holy Orthodox faith cannot be reduced to systematic theology precisely because it is not only a set of dogmas; but it is the fullness of the Faith that no-other-sect posesses. This fullness is the entirety of Holy Tradition - preserved with love and piety, even to the point of martyrdom, by the faithful of the generations before us - without the distinction to what is great or small according to human understanding. Do you neglect or cut away with the parts of your own flesh you deem insignificant while preserving in health the parts that you hold in honor? Equally then, do not part the body that is the living Church and do not decide for yourself which is small or great; which you shall follow with zeal and which you shall dispise - for 'he that is faithful in that which is least is faithful also in much: and he that is unfaithful in the least things is unfaithful also in much.' - Luke 16:10. When the small things are cut off, as for example the springs and streams which feed the river cease to be nourished, the river shall also eventually run dry. Let us therefore with the zeal that is born of love hold onto even the small things which have been given to us for the sake of our salvation and entrusted to us for the salvation of the whole world; not begrudging their simplicity against them; but valuing them all the more for it. For as from the small mustard seed, which is the least in the eyes of man, springs forth great branches for the birds of heaven to come down and dwell upon, so the zeal and love for small things leads us to the greater zeal and love for the Orthodox Faith where the Spirit of God shall be pleased also to come down and dwell.