大方廣圓覺修多羅了義經略疏 2.302

2.302

Now, the purpose of establishing words and images lies in grasping the meaning. Without words and images, one is inverted and confused; yet by clinging to words and images, one is deluded about the real. Therefore, the finger pointing at the moon is used as a metaphor for verbal teachings. To see the moon, one must rely on the tip of the finger; to awaken to the mind, one must borrow the Buddha’s teachings. By means of the finger, one sees the moon; having seen the moon, one forgets the finger. By means of the teaching, one snares the mind; having awakened to the mind, one forgets the teaching. Retaining the finger, one loses the true moon; clinging to the teaching, one loses the original mind. The intent is to cause one to realize the real and forget what points to it, which is why it says, 'ultimately not the moon.'