Listen to Harden Not Your Heart (Duet) (Radio Edit) online. Harden Not Your Heart (Duet) (Radio Edit) is an English language song and is sung by Nicholas Mazzio, Lauren Mazzio and The Rain. Harden Not Your Heart (Duet) (Radio Edit), from the album The Spirit Of The Lord Is Upon Me Album (Written and Performed By Nicholas Mazzio), was released in the year 2025. The duration of the song is 6:23. Download English songs online from JioSaavn.