Gregory the Dialogist

And before the fronts was a picture of palm trees. What is designated by palms, if not the rewards of victory? For these are customarily given to victors. Hence also concerning those who in the contest of martyrdom had conquered the ancient enemy, and were now rejoicing as victors in their homeland, it is written: "And palms in their hands, and they cried out with a loud voice, saying: Salvation to our God, who sits upon the throne, and to the Lamb." For to have palms in their hands is to have held fast to victories in their deeds. …

Homilies on Ezekiel, Book 2, Homily 5 ↗