Peter's great confession of faith: that Jesus was the Messiah. He was correct. He was even inspired by the Father to make that statement of faith.
But when Jesus began to openly teach the necessity of the Cross, Peter - of all people - took Him aside, and began to rebuke Him. This the sternest rebuke that Jesus ever gave (Mark 8:31-33).
Was this the "more opportune time?" Hard enough to endure temptation from Satan, but what about those from your friends...?
Also notice the "get behind.." Jesus had called Peter to follow Him; now Peter was trying to talk Jesus into following what Peter wanted instead.
Taking up the Cross
If you wish to follow Jesus, you must learn self-denial. You must “deny yourself” (Mark 8:34). The Christian life involves choosing the way of God rather than our own path. You must follow the example of Jesus, who surrendered Himself to the will of His Father (Luke 22:42).
If you would follow Jesus, you must be willing to walk with Him, and to go wherever He leads.
Sometimes this is spending a life in service, like Rev. Graham. For others, it has been giving up their lives for Christ, as Rev. Bonhoeffer.
It means surrendering our goals to God. That's hard...
We are told by this world to place our will at the forefront
"I am the master of my fate, I am the captain of my soul."- from Invictus by William Ernest Henley
And yet the message of Christ still shines through the lives of His children:
In her book, Out of the Saltshaker and into the World, Rebecca Manley Pippert relates that she was afraid of becoming a Christian, because (she thought) she would cease to be herself. But surprise! In losing herself to Christ she found the authentic "self" she was always meant to be. The truth was that in Sacrifice she found Victory.
You have a choice: Savior or Self
“The opposite of wasting your life is to live by a single, soul-satisfying passion for the supremacy of God in all things. If you want your life to count, if you want the ripple effect of the pebbles you drop to become waves that reach the ends of the earth and roll on into eternity, you have to know one great all-embracing thing—and be set on fire by it. Like Paul, declare, ‘I decided to know nothing among you except Jesus Christ and him crucified.’” (Don’t Waste Your Life, p. 43-44)