As David experienced, the consequences of sitting out the Lord’s battles may be a devastating personal moral failure. Comparison of two incidents in David’s life should bring this lesson home to us and warn us of the same possibilities in our own lives.

The first incident is before David became king of Israel, 1 Samuel 25. David is very angry at Nabal for insulting him and snubbing him and acting ungratefully, and vows to kill every male belonging to him. Foolish Nabal has a wise wife Abigail who learns of the danger and appeals to David not to take vengeance for himself, because it is necessary that the one who is fighting the Lord’s battles be blameless: "The Lord will certainly make for my lord an enduring house, because my lord is fighting the battles of the Lord, and evil will not be found in you all your days" (v. 28). If David avenges himself now, then when he becomes king his satisfaction at the fulfillment of the Lord’s promises to him will be marred by a guilty conscience for having shed innocent blood (vv. 30–31). 

The idea of David fighting the battles of the Lord goes back to David's appearance on the public scene, as he alone in Israel is willing to fight Goliath (1 Samuel 17).  When Saul says to David, "You are not able to fight him" he is virtually quoting the unbelieving spies in the wilderness, who said "we are not able" to fight the giants of Canaan (Numbers 13), and were thus sentenced to die outside the promised land.  In saying "you are not able," and in not himself going to fight, Saul shows himself unworthy of possession of the promised land, and the same goes for the rest of his army.  But David goes to battle with the words "I come to you in the name of the Lord of Hosts," etc., words echoed in Psalm 118 looking forward to the coming one, "Blessed is he who comes in the name of the Lord," alluded to by Jesus in John 5:43, "I have come in my Father's name," as Jesus comes to defeat the devil on the cross.

David is won over by Abigail, and blesses the Lord for sending Abigail to him, thus keeping him from shedding innocent blood (vv. 32–33).

The outcome is that the Lord kills Nabal, and David marries Abigail.

The next incident, as you can anticipate, is after David has become king. 2 Samuel 11 begins, "At the time when kings went forth [to war], … David stayed in Jerusalem." With so many battles and victories behind him, David stays home, where he sees Bathsheba, covets her, commits adultery, and then murder to try and cover up the adultery. During all that time, unlike in 1 Samuel 25, the Lord does not send anyone to stop David from sinning. Why? Remember why the Lord sent Abigail to stop David from sinning? Because David must be blameless, "because my lord is fighting the battles of the Lord." By slacking off from the battle, David became vulnerable to moral temptation and failure. David is sending, sending, sending throughout this chapter, but the Lord did not send anyone to David until his sin had run its course to the full fruit of murder. This is part of the spiritual calculus that we must learn from the Scriptures, and we are foolish if we think we are above a similar failure.

Application? Paul tells Timothy "Fight the good fight of faith" (1 Tim 6:2) and says of himself later, "I have fought the good fight" (2 Tim 4:7). Paul was a good example of obedience to the requirement to "take up your cross daily and follow me" (Matt 16:24, etc.). To take up one’s cross is to risk death. We Americans are such wimps, we worry about being sued, or losing a job, or a pension. So, my brothers, join the battle, don’t hold back for fear someone will read your name on the internet. What can anyone do to you that is worth the price of not being able to say "I have fought the good fight, I have finished my course, from now on there is laid up for me the crown of righteousness, which the Lord, the righteous judge, will award to me on that day."