Retreat is a term we do not like. We think of it as failing or quitting, with an accompanying sense of shame. Surrender, which of course is linked to retreat, is also very difficult.
But it is to the ideal of surrender that we are called in the spiritual life. We are called to retreat. We are not to be like Ulysses S. Grant, who famously wrote in May 1864 to the War Department of his plans to do anything but retreat against Lee's army. "I propose to fight it out on this line if it takes all summer," he said. Christ surrender on the cross. So too are we.