17:1 on the tablet of their heart. This metaphor recalls tablets for writing laws. See 31:33, where the law will be written on the heart, and Prov. 3:3; 7:3. In the new covenant, Christ writes the law on His people’s hearts by His Spirit (2 Cor. 3:3).

on the horns of their altars. These altars should commemorate atonement for sin, but where the sin is unforgiven they continue to remind God of the sin itself.