Tolkien is one of those reliably wise souls. Even when we are pretty sure we know what we’re doing, we should “not be too eager” in matters of life and death.
Want a hard one? Apply this to your urge to “rally the troops” to any side of a life-and-death issue. There are always some among us who are “too eager” to find the very most radical edge: curb your urge to hurl them against the wall (or the enemy), or you may destroy them–and yourself. In the middle of all that, the loss of your cause will come to be trivial. Then you will see, too late, why you ought not to have been “too eager.”