The rebuking of Peter
20 Then he ordered his disciples not to tell anyone that he was the Messiah.
Jesus Predicts His Death
21 From that time on Jesus began to explain to his disciples that he must go to Jerusalem and suffer many things at the hands of the elders, the chief priests and the teachers of the law, and that he must be killed and on the third day be raised to life.
22 Peter took him aside and began to rebuke him. “Never, Lord!” he said. “This shall never happen to you!”
23 Jesus turned and said to Peter, “Get behind me, Satan! You are a stumbling block to me; you do not have in mind the concerns of God, but merely human concerns.”
24 Then Jesus said to his disciples, “Whoever wants to be my disciple must deny themselves and take up their cross and follow me.
How to understand self renunciation?
Saint Basil the Great, Big rules, Cap. II, Î. 8, R. I, in Church Fathers and Writers (1989), vol. 18, p. 235
„(…) The one who renounces at himself takes out the old man with his deeds (Colossians 3, 9), the one corrupted by the desires of delusion (Ephesians 4, 22).
He gets rid of the worldly passions which can impede the aim of piety. A man like this will consider as real parents those who gave him birth in Jesus Christ through the Gospel (I Corinthians 4, 15), and as brothers those who received the same spirit of adoption and will consider all fortunes as foreign as they really are. In a word, how can one share the concerns of the world when the whole world was crucified through Christ for him and he was crucified for the world as well? (Galatians 6, 14)”
Saint John Chrysostom, Homilies at Matthew, Homily LV, I, in Church Fathers and Writers (1994), vol. 23, p. 635
Renounce at yourself, meaning to have nothing in common with yourself, but face dangers and works ; you should have such a soul as if it`s not you who suffers these but someone else. He didn`t say to deny himself but to renounce at himself. To renounce at yourself is more than to deny yourself and to take his cross. Taking his own cross is a result of self renunciation.
For not considering that to renounce at yourself means only to suffer bad words, slanders and insults, Christ says until where self renunciation must go, until death, even a shameful one. That is why He didn`t say `to renounce at himself until death but `to take his cross showing the shameful death and this should not be done only once or twice but the entire life.
Saint Basil the Great, Small rules, Î. 237, in Church Fathers and Writers (1989), vol. 18, p. 419
Question 237: What soul guides itself towards the will of God ? Answer: Who received the call of God Who said: If someone comes to Me, he should renounce at his self and take his cross and follow Me (Matthew 16, 24; Luke 14, 26).
If someone can`t renounce at himself first and take his cross, will find when he goes further many obstacles which come from his own self impeding him to follow the Lord.`