1 Samuel 21
David was still on the run from Saul when he came to Nob, where he met Ahimelech the priest. When confronted by Ahimelech about traveling alone, it seems that David panicked and lied about his "mission" so as not to alarm anyone. He explains that he was secretly sent by the King. David asks for food and a weapon, which didn't really go well with his story that he was to meet soon with his men. When he was discovered by the servants of Achish, they said "Can this be the famous Daivd?... the one they sing 'Saul kills by the thousand, David by the ten thousand!'" David feared the worst and pretended to go crazy and so Achish sent him away.