1 Samuel 23:6

When Abiathar … fled to David to Koilah, he came down with an ephod in his hand. Literally, "an ephod came down in his hand, and so, word for word, the Syriac. The object of this verse is to explain how it was that David (in 1 Samuel 23:2 and 1 Samuel 23:4 ) was able to inquire of Jehovah. The words to Keilah —Hebrew, Kelah-wards—do not mean that it was at Keilah that Abiathar joined David, but that he came in time to go thither with him. In 1 Samuel 22:20 it seems as if Abiathar must have joined David even at an earlier date, for he is represented as fleeing to him immediately after the massacre of the priests at Nob. Now, granting that David's stay at Gath with Achish was very brief, he must have remained at Adullam a considerable time, inasmuch as men joined him there in large numbers ( 1 Samuel 22:2 ), which seems to show that his hiding place had become generally known. It was probably this concourse of men to him that was "discovered," i.e. made known, to Saul, and, as being an act of formal revolt, so raised his ire. As being supposed to be in league with David, Saul put the priests to death, and Abiathar fled; but probably the news of this terrible act had already reached David, and, in anxiety about his father and mother, he had gone to find refuge for them in Moab. Thither Gad follows him, bringing prophetic approval of his conduct, but ordering him to return into the territory of his own tribe. If then David was on his way to Moab when Abiathar reached Adullam, he may have remained in hiding there till David's return to the thickets of Hareth. But, possibly, even before Abiathar joined him the news may have arrived of the Philistine foray, and David's mind was set Keilah-wards. But there were those who doubted of the prudence of this proceeding, and Abiathars arrival with the ephod enabled him to consult Jehovah's will. By his presence also David had now the approval of the priesthood.