《申命记》三十三章的第十节：In a desert land he found him, in a barren and howling waste. He shielded him and cared for him; he guarded him as the 'apple of his eye'。跟东方一样，在西方，人们也一直都把苹果视为一种吉祥的水果。不是还有另一句英文谚语："An apple a day, keeps doctor away"。所以"apple of one's eye"就是指「珍贵的东西」，也就常被引申为「珍爱的人或物」。所以说You are the apple of my eye，意思就是指说：你是我的挚爱，或是同等意思。