From Ray Ortlund.

When Peter said to Jesus, “You are the Christ, the Son of the living God,” the Lord replied, “Blessed are you, Simon Bar-Jonah!  For flesh and blood has not revealed this to you, but my Father who is in heaven” (Matthew 16:16-17).  Peter’s declaration was not from his own mind.  God gave Peter a new sense on his heart of the true glory of Jesus.  Peter’s decisiveness was the touch of grace from above.

What happened next, therefore, is astonishing.  When Jesus pointed to the cross, “Peter took him aside and began to rebuke him, saying, ‘Far be it from you, Lord!  This shall never happen to you’” (Matthew 16:22).  Peter began dictating to Jesus how world redemption was (or was not) to be gained, and no way would there be a cross!  Peter’s heart must have been swelling with emotions of loyalty to Jesus.  But the Lord saw what was really happening.  He confronted Peter with these disturbing words: “Get behind me, Satan!  You are a hindrance to me” (Matthew 16:23).

God illuminates Peter’s mind.  Then Satan speaks through the same Peter.  Jonathan Edwards warned us: “It is a grand error for persons to think they are out of danger from the devil and a corrupt, deceitful heart, even in their highest flights and most raised frames of spiritual joy.”

Did Peter choose to lend himself to evil?  No.  Jesus explains how he went wrong: “You are not setting your mind on the things of God, but on the things of man” (Matthew 16:23).  Peter didn’t have to set his mind on the things of Satan to be useful to Satan; all he did was set his mind on the things of man.  If not identical with “the things of God,” “the things of man” seem distant enough from “the things of Satan” to be plausible, even hopeful.  But Jesus can see that the reasonable “things of man” and the horrible “things of Satan” are both opposed to the redemptive “things of God,” so diametrically opposed that “the things of man” can serve “the things of Satan.”

What then are “the things of man” that exposed Peter’s heart to Satanic evil?  The very understandable human instinct of self-preservation.  So Jesus made it clear: “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 will find it” (Matthew 16:24-25).

Any time you and I reject the cross and, in effect, rebuke our Lord for choosing that path for himself and us, can we be sure what influence will come out of our mouths next, even if we have also served as voices for God?  At the moment we might not even be aware of the difference.  Peter wasn’t, until Jesus reproached him.

Every day we face decisions that require us to die.  We may find ourselves thinking a very human thought like, “Far be it from me, Lord!  This shall never happen to me.  I cannot allow myself to lose, to be diminished, to be set aside, to be misunderstood and misjudged.”  But if we set our own preconditions on the Lord, we might hear him say to us, as in fact he said to no one less than the apostle Peter, “You are a stumbling block to me.  You do not understand that new life always comes through death.  If you want to follow me there, I welcome you to.  But you’ll have to pick that cross back up again.  Yes, the one you just threw away.”

In the dying words of the Scottish martyr John Nisbet, “Be not afraid of his sweet, lovely and desirable cross.”