Mark 8:34 And when he had called the people unto him with his disciples also, he said unto them, Whosoever will come after me, let him deny himself, and take up his cross, and follow me.
After Peter's rebuke after the heart of a sinful man, Jesus said we must die to our flesh mind, deny ourselves, and take up our cross. We are to put our old nature on the cross with its natural way of seeing and thinking, and follow Jesus. We follow him today by following the Holy Spirit that he left for us.
Mark 8:35 For whosoever will save his life shall lose it; but whosoever shall lose his life for my sake and the gospel's, the same shall save it.
You want your own way? You want a life as a sinner? That life shall perish; but if you give up your self-will, losing your life and serving the will of God, preaching the good news? You shall save your life, for eternity in Christ Jesus.
Mark 8:36 For what shall it profit a man, if he shall gain the whole world, and lose his own soul?
You want all you can get of the things of this life? Give all to God and he will give you all you need that is good for you. You shall save your soul through faith in Jesus Christ.
Mat 6:33 But seek ye first the kingdom of God, and his righteousness; and all these things shall be added unto you.
Mark 8:37 Or what shall a man give in exchange for his soul?
Nothing can compare to eternal life and escaping hell.
Mark 8:38 Whosoever therefore shall be ashamed of me and of my words in this adulterous and sinful generation; of him also shall the Son of man be ashamed, when he cometh in the glory of his Father with the holy angels.
So you want to be a person of the world at all costs? It may cost you your soul, don't do that. Do not be ashamed of Jesus in this life so that he will receive you in the next life. Flesh dies, the soul lives forever in heaven or in torment. This is the truth of God.
Jer 17:9 The heart is deceitful above all things, and desperately wicked: who can know it?
Jer 17:10 I the LORD search the heart, I try the reins, even to give every man according to his ways, and according to the fruit of his doings.