"The point is that no matter what kind of suffering we have to endure, God always gives us a way out.
Not a way out of the suffering itself—but from the utter, black hopelessness that suffering can lead us into.
And that's what this prayer is—a way out of hopeless despair.
In a famous passage from his first letter to the Corinthians, the apostle Paul says that God "will not let you be tested beyond your strength. With your trial, he will also provide you with a means of escape, so that you will be able to endure it."
Spiritual writers often use that passage to illustrate that God will never allow us to be tempted to sin beyond the point that we can resist.
But it applies just as much to suffering.
God always gives us an "escape hatch."
No matter how great our inner turmoil, he always gives us an exit through which we can go to avoid being trapped.
When Christ prayed that he be spared the agony of the Crucifixion, God may have denied his request, but he promptly dispatched an angel to the Garden of Gethsemane to comfort him.
The angel stayed with the Lord and consoled him, strengthened his resolve, and essentially helped him to get through the deep emotional turmoil and dread he was experiencing.
That's the same model of assistance God employs with us.
Our appointed sufferings may or may not be prevented through prayer—depending on the situation and on God's will—but we, ourselves, can ALWAYS count on being helped, consoled, and fortified by God - if we ask for help."
- From "Experiencing God Day by Day " by Richard Blackaby