Cross reference
Mark 4:23
23 If any man has ears to hear, let him hear."
Matthew 11:15
15 He who has ears to hear, let him hear.
Mark 4:9
9 He said, "Whoever has ears to hear, let him hear."
Revelation 2:7
7 He who has an ear, let him hear what the Spirit says to the assemblies. To him who overcomes I will give to eat of the tree of life, which is in the Paradise of my God.
Revelation 2:11
11 He who has an ear, let him hear what the Spirit says to the assemblies. He who overcomes won't be harmed by the second death.
Revelation 2:17
17 He who has an ear, let him hear what the Spirit says to the assemblies. To him who overcomes, to him I will give of the hidden manna,{Manna is supernatural food, named after the Hebrew for "What is it?". See Exodus 11:7-9.} and I will give him a white stone, and on the stone a new name written, which no one knows but he who receives it.
Revelation 2:29
29 He who has an ear, let him hear what the Spirit says to the assemblies.