According to another explanation the album’s title refers to a verse in the Bible (Psalm 31:21). “Blessed be Jehovah (God/Yahweh), For he has rendered wonderful loving-kindness to me in a city under stress.” Prince made a reference to this during a performance of the title track on the 2006 BET Awards; “Where’s the real party at? Shake your tambourines! BET read Psalms; that’s where it is.”
A further explanation reveals that 3121 refers to the album being Prince’s 31st release and the release date being the 21st.