Gregory the Great — as excerpted in the Catena Aurea on Luke 21:28-33

“(Hom. 1. in Ev.) Having in what has gone before spoken against the reprobate, He now turns His words to the consolation of the elect; for it is added, When these things begin to be, look up, and lift up your heads, for your redemption draweth nigh; as if he says, When the buffettings of the world multiply, lift up your heads, that is, rejoice your hearts, for when the world closes whose friends ye are not, the redemption is near which ye seek. For in holy Scripture the head is often put for the mind, for as the members are ruled by the head, so are the thoughts regulated by the mind. To lift up our heads then, is to raise up our minds to the joys of the heavenly country.”