#How did Abishai rescue David when he was overcome with battle fatigue?

When David was overcome with battle fatigue, Abishai rescued him by killing Ishbibenob the Philistine who had intended to kill David. [21:15-17]

#Why did the men of David insist that he not go into battle with them anymore?

The men of David insisted that David not go into battle with them anymore because they were afraid that the lamp of Israel might be put out. [21:17]