Summary: The life of the disciples must be lived for Christ's sake and not for the disciple's comfort.
“[Jesus] began to teach them that the Son of Man must suffer many things and be rejected by the elders and the chief priests and the scribes and be killed, and after three days rise again. And he said this plainly. And Peter took him aside and began to rebuke him. But turning and seeing his disciples, he rebuked Peter and said, ‘Get behind me, Satan! For you are not setting your mind on the things of God, but on the things of man.’
“And calling the crowd to him with his disciples, he said to them, ‘If anyone would come after me, let him deny himself and take up his cross and follow me. For whoever would save his life will lose it, but whoever loses his life for my sake and the gospel’s will save it. For what does it profit a man to gain the whole world and forfeit his soul? For what can a man give in return for his soul? For whoever is ashamed of me and of my words in this adulterous and sinful generation, of him will the Son of Man also be ashamed when he comes in the glory of his Father with the holy angels.’” 
“For Christ’s sake!” The oath is frequently heard in conversation in our day. Though it adds nothing to the conversation, the frequent and thoughtless oath is blurted out for emphasis. Its use may express exasperation, a sense of awe or simply serve as a tag line for emphasis. Tragically, the words find their way too often into the conversation of believers. The reason I say “tragically” is that seldom are we speaking of our service to God when the phrase escapes our lips. Rather than speaking the language of Zion, we speak the language of this dying world. However, I hope with this message today to challenge us to think of what we do and why we do what we do on an ongoing basis. Are our choices truly for Christ’s sake? Or are we prone to do what we want, even in the congregation of the righteous?
I am not castigating anyone for coarse language, though the Bible does caution us against such speech. Christians are taught, “Let there be no filthiness nor foolish talk nor crude joking, which are out of place, but instead let there be thanksgiving” [EPHESIANS 5:4]. Perhaps more disturbing than the knowledge that such language is even found among God’s people is the association of such speech with other unrighteous acts. The Apostle continues by warning, “You may be sure of this, that everyone who is sexually immoral or impure, or who is covetous (that is, an idolater), has no inheritance in the kingdom of Christ and God. Let no one deceive you with empty words, for because of these things the wrath of God comes upon the sons of disobedience. Therefore do not become partners with them” [EPHESIANS 5:5-7].
In that same missive, the Apostle warned against “corrupting talk,” or “foul language.” He wrote, “No foul language is to come from your mouth, but only what is good for building up someone in need, so that it gives grace to those who hear”  [EPHESIANS 4:29]. These warnings from the Ephesian Letter are similar to the warning that was given to the Church in Colossae. “Make sure [that ungodliness and immorality is] all gone for good: bad temper, irritability, meanness, profanity, dirty talk”  [COLOSSIANS 3:8]. However, our speech as Christians is not the focus of the message. Our walk with the Master is the focus of the message.
IF WE WILL WALK WITH THE MASTER, WE WILL DENY OURSELVES—FOR CHRIST’S SAKE. “If anyone would come after me, let him deny himself.” Jesus had just spoken of His Passion; Peter took Him aside and began to rebuke Him. Imagine that! The Master had just spoken of His sacrifice, and Peter—impetuous Peter—began to rebuke Him! However, Jesus turned and noting that the disciples were watching closely sharply rebuked Peter. “Get behind me, Satan! For you are not setting your mind on the things of God, but on the things of man” [MARK 8:33].
Do you not find it shocking that Peter would attempt to dress down the Master? Don’t be too harsh on Peter; such actions may not be as unusual as we imagine. We do similar things, discounting the commands of Jesus when our desires take precedence over what He is saying. When we exalt ourselves, we do so at the expense of the revealed will of Jesus. In these cases, it is as though we were rebuking Him, telling Him that we are much better at controlling our lives than he is at directing how we should live. Let me give a few examples of what I mean by this.