Concise Bible Dictionary:
The organ of hearing is often used symbolically in scripture. When a servant, whose time of service had expired, preferred to stay with his master, saying, “I love my master, my wife, and my children; I will not go out free,” his ear was bored with an awl to the door post, and his ear belonged to his master perpetually, he was to hear only that one as master: type of Christ and His love to the church (Ex. 21:5-6; Deut. 15:17). Of Christ also it is said, “mine ears hast thou opened” (Psa. 40): quoted in Hebrews 10:5 from the LXX, “a body hast thou prepared me,” both signifying that He was the obedient one. “He that hath ears to hear, let him hear” was said by the Lord to His hearers, and to each of the seven churches in Asia, and also said when the beast, representing the future Roman power, is worshipped, signifying that a spiritual discernment was needed to catch the meaning of what was uttered (Matt. 13:9,43; Rev. 2:7,11,17,29; Rev. 3:6,13,22; Rev. 13:9).
Strong’s Dictionary of Greek Words:
Meaning:
apparently a primary word; the ear (physically or mentally)