1)
What is the connection of taking in your heart and hearing in your ears?
1.
Radak: Take in your heart after you hear in your ears, lest you forget what you heard. The prefix Vov in uv'Aznecha [means after, like] "Atah Katzafta v'Necheta" (Yeshayah 64:4) - after we sinned, You became angry.
2.
Malbim: This Navi will have many visions, e.g. Ma'ase Merkavah and the future Bayis. He should take the matters in his heart - this requires preparing the heart. Hear in your ears what you are sent to rebuke them.