The 21 chapters are short, and continuing with the letter from Ignatius to the Ephesians three chapters at a time.
Note that there were false teachers, heresiarchs, and those who preach comfort, spirituality, and Satanic lies instead of the true gospel. Nothing has changed.
Do not err, my brethren. Those that corrupt families shall not inherit the kingdom of God. If, then, those who do this as respects the flesh have suffered death, how much more shall this be the case with any one who corrupts by wicked doctrine the faith of God, for which Jesus Christ was crucified! Such an one becoming defiled [in this way], shall go away into everlasting fire, and so shall every one that hearkens unto him.
For this end did the Lord suffer the ointment to be poured upon His head, that He might breathe immortality into His Church. Be not ye anointed with the bad odour of the doctrine of the prince of this world; let him not lead you away captive from the life which is set before you. And why are we not all prudent, since we have received the knowledge of God, which is Jesus Christ? Why do we foolishly perish, not recognising the gift which the Lord has of a truth sent to us?
Let my spirit be counted as nothing for the sake of the cross, which is a stumbling-block to those that do not believe, but to us salvation and life eternal. “Where is the wise man? where the disputer?” Where is the boasting of those who are styled prudent? For our God, Jesus Christ, was, according to the appointment of God, conceived in the womb by Mary, of the seed of David, but by the Holy Ghost. He was born and baptized, that by His passion He might purify the water.
Ignatius, Letter to the Ephesians