''My love wasn't true/Now all I have is you/Jesus, oh Jesus/I don't want to die alone,'' sings Josh Haden, son of famed jazz bassist Charlie Haden, on the plainspoken ''Spiritual.'' It's a song that tells you more about the root of religiosity than any dozen conventional gospel tunes. And it's just one in a set of sumptuously sad numbers by Haden's short-lived group, who put out three down-tempo, dark blue LPs that mixed jazz and old-fashioned pop with a hushed indie-rock sensibility before folding in 2001. If their debut had been released now, they'd probably be playing amphitheaters with Norah Jones. But in music, as in life, timing is everything. SIBLING RIVALRIES Haden's sisters, Rachel and Petra, were in L.A.-based 1990s alt-pop outfit That Dog, whose records are worth hunting for.