Midrash sobre I Samuel 23:1

(Fol. 45a) R. Juda, in the name of Rab, said: "If heathens besieged a town inhabited by Israel, the latter were not permitted to meet them with war implements on the Sabbath." We have also a Baraitha to the same effect: "If idolaters besieged," etc. In what case do these words apply? When the enemy came because of monetary matters; but if their coming involve human lives, they should be met [even on the Sabbath] with implements of war. If the enemy invaded towns near the boundary [of Palestine] they should be met with implements of war [on the Sabbath] even if the invasion does not involve danger of life, but involves the robbery of even such a common article as straw." R. Joseph b. Minyumi said in the name of R. Nachman: "Babylon is considered [in respect to meeting an invasion with war implements on the Sabbath] as a city near the boundary." This refers only to Neharde'a. R. Dostai of Biri expounded: "What is meant by the passage (I Sam. 23, 1.) Then they told David, saying. 'Behold, the Philistines are fighting against Ke'ilah, and they are plundering the threshing-floors'? We are taught that Ke'ilah was a city situated near the boundary and the invaders came solely for the purpose of seizing straw and hay, as it is written They are plundering the threshing-floors; it is also written (Ib. ib. 2.) Thereupon David asked counsel of the Lord, saying, 'Shall I go and smite among these Philistines?' And the Lord said unto David, 'Go and smite among the Philistines and deliver Ke'ilah.' Now, what did David ask of the Lord? Shall we assume that he asked whether he was permitted to go out against the Philistines or not? This should have been asked of the court tribunal, at that time sitting in Ramathi and of which Samuel [the prophet] was the head. We must therefore conclude that he asked of the Lord whether he would succeed or not. This conclusion can also be proved from [the reply given them] which is written there, Go and smite among the Philistines and deliver Ke'ilah. [This indicates that the Lord meant to secure David's success.] The conclusion is therefore accepted.