The officers shall speak further to the people, and say, “What man is there who is fearful and fainthearted? Let him go and return to his house, lest the heart of his brethren faint like his heart.”~ Deuteronomy 20:8— • —
So time and the hopeless journey wore away. Upon the fourth day from the Cross Roads and the sixth from Minas Tirith they came at last to the end of the living lands, and began to pass into the desolation that lay before the gates of the Pass of Cirith Gorgor; and they could descry the marshes and the desert that stretched north and west to the Emyn Muil. So desolate were those places and so deep the horror that lay on them that some of the host were unmanned, and they could neither walk nor ride further north.
Aragorn looked at them, and there was pity in his eyes rather than wrath; for these were young men from Rohan, from Westfold far away, or husbandmen from Lossarnach, and to them Mordor from childhood had been a name of evil, and yet unreal, a legend that had no part in their simple life; and now they walked like men in a hideous dream made true, and they understood not this war nor why fate should lead them to such a pass.
“Go!” said Aragorn. “But keep what honour you may, and do not run! And there is a task which you may attempt and so be not wholly shamed. Take your way south-west till you come to Cair Andros, and if that is still held by enemies, as I think, then re-take it, if you can; and hold it to the last defence of Gondor and Rohan!”
Then some being shamed by his mercy overcame their fear and went on, and others took new hope, hearing of a manful deed within their measure that they could turn to, and they departed.
~ J.R.R. Tolkien, The Return of the King,
Chapter 10: “The Black Gate Opens”