# detained before Yahweh

"for some work before Yahweh" or "because Yahweh had detained him there" 

# Doeg ... shepherds

"Doeg ... herdsmen, and he saw what Ahimelech did". You may need to say clearly that Doeg saw what David did. 

# Doeg the Edomite

This is the name of a man from the land of Edom.