It's Idle/Idol Worship
Multiple levels or entendres to this phrase:
Idle Worship could represent how the youth have so little options and a lack of purpose that even their “worship” is done idly — without much meaning or emphasis.
Idol Worship — in the sense that people will do nearly anything for money, they almost worship materialism. This connects with the earlier “praying to the dollar sign” lyric. Many religions, warn against this kind of “worship”
Idle Warship (Talib Kweli & Res)
I believe “idol/idle” worship should be reversed to read “idle idol” worship. The sentence only makes sense if it suggests that the worship of an idol is being done idly (i.e. with no purpose or reason) given the context of the song. “Prayin' to the dollar sign” refers to the lack of purpose (idle) given to the idol of money. This lyric is meaningless otherwise.
To help improve the meaning of these lyrics, visit "Lost Desire" by The Roots (Ft. Malik B, Mercedes Martinez & Talib Kweli) Lyrics and leave a comment on the lyrics box