Ear

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. 21:5-65And if the servant shall plainly say, I love my master, my wife, and my children; I will not go out free: 6Then his master shall bring him unto the judges; he shall also bring him to the door, or unto the door post; and his master shall bore his ear through with an aul; and he shall serve him for ever. (Exodus 21:5‑6); Deut. 15:1717Then thou shalt take an aul, and thrust it through his ear unto the door, and he shall be thy servant for ever. And also unto thy maidservant thou shalt do likewise. (Deuteronomy 15:17)). Of Christ also it is said, “mine ears hast thou opened” (Psa. 40): quoted in Hebrews 10:55Wherefore when he cometh into the world, he saith, Sacrifice and offering thou wouldest not, but a body hast thou prepared me: (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. 13:9,439Who hath ears to hear, let him hear. (Matthew 13:9)
43Then shall the righteous shine forth as the sun in the kingdom of their Father. Who hath ears to hear, let him hear. (Matthew 13:43)
; Rev. 2:7,11,17,297He that hath an ear, let him hear what the Spirit saith unto the churches; To him that overcometh will I give to eat of the tree of life, which is in the midst of the paradise of God. (Revelation 2:7)
11He that hath an ear, let him hear what the Spirit saith unto the churches; He that overcometh shall not be hurt of the second death. (Revelation 2:11)
17He that hath an ear, let him hear what the Spirit saith unto the churches; To him that overcometh will I give to eat of the hidden manna, and will give him a white stone, and in the stone a new name written, which no man knoweth saving he that receiveth it. (Revelation 2:17)
29He that hath an ear, let him hear what the Spirit saith unto the churches. (Revelation 2:29)
; Rev. 3:6,13,226He that hath an ear, let him hear what the Spirit saith unto the churches. (Revelation 3:6)
13He that hath an ear, let him hear what the Spirit saith unto the churches. (Revelation 3:13)
22He that hath an ear, let him hear what the Spirit saith unto the churches. (Revelation 3:22)
; Rev. 13:99If any man have an ear, let him hear. (Revelation 13:9)).

From Manners and Customs of the Bible:

The Psalmist uses this expression to denote the fact that he is a servant of God, ready to do his will, as he further declares in the eighth verse. He seems to have in his mind the ceremony by which a Hebrew servant, if unwilling to leave his master, might be bound to him for life. “Then his master shall bring him unto the judges; he shall also bring him to the door, or unto the door post; and his master shall bore his ear through with an awl; and he shall serve him forever” (Ex. 21:66Then his master shall bring him unto the judges; he shall also bring him to the door, or unto the door post; and his master shall bore his ear through with an aul; and he shall serve him for ever. (Exodus 21:6)). See also Deuteronomy 15:16-1716And it shall be, if he say unto thee, I will not go away from thee; because he loveth thee and thine house, because he is well with thee; 17Then thou shalt take an aul, and thrust it through his ear unto the door, and he shall be thy servant for ever. And also unto thy maidservant thou shalt do likewise. (Deuteronomy 15:16‑17). This custom was observed, not only by the Jews, but also by many other ancient nations.