Despite the failure of David's former solo jaunt to Gath, David and his 600 tried out the welcome there again. And, although it took some deception on the part of David and his men, it worked out well for them. Achish gave them Ziklag for their hangout, and David took advantage of that offer for 16 months. During his stay, he obliterated the inhabitants of several different Gentile towns and villages. Not only that, but he led Achish to believe that he was killing Jews. So Achish was confident that David had truly defected to his side.
Even though he was far from home and was seemingly far from his calling, David's heart was aimed in the right direction. He was fighting for his people (the Jews) and against their enemies.
This story reminds me of Jesus' prayer as it was recorded in John 17:15, "I pray not that You should take them out of the world, but that You should keep them from the evil." David wasn’t close to the Tabernacle. He wasn't in a position where he could openly and loyally serve the rightful king of Israel. He was seemingly at a distinct disadvantage in relation to what God had planned for him to do ultimately in Israel. Yet, he found a way to accomplish things that fit well with his overall purpose.
How about with you and me? Do we sometimes just sit around spiritually, waiting for a more convenient opportunity to present itself? Why not fight the devil where we are with whatever tools we have? If we wait for the perfect opportunity, we'll miss out on some great ones along the way. In a secular workplace, among unregenerate family members, in the middle of a debilitating illness, in the loss of loved ones and friends, or wandering nearly alone down the lane toward the sunset of your life... keep on keeping on. As Theodore Roosevelt supposedly said, "Do what you can, with what you have, where you are." That's what David did. That's what you and I should do too.