1 Samuel 30:6 says, “And David was greatly distressed; for the people spake of stoning him, because the soul of all the people was grieved, every man for his sons and daughters; but David encouraged himself in The Lord.”
 
David was anointed to replace Saul several years before the time when he encouraged himself; however, Saul wasn’t ready to step down from being King even though God was not leading him any longer. As you remember, Saul’s primary mission in life was to kill David so his children would succeed him on the throne and not David. 
 
David went from being used by God to soothe and minister to his King to being anointed his successor and then running for his life. In 1 Samuel 30:6, David began to fight for the Philistine army when they were fighting against the enemies of Israel. He had a group of rag-tag followers who were outcasts who fought alongside him. When the Philistines would fight against Israel, however, they wouldn’t allow David and his mighty men to fight with them, in fear they would fight for Israel and turn on them. For this reason, David and his men were returning home to Ziklag after being rejected by the Philistines when they found their camp had been seized by another enemy who took their wives, sons, and daughters. At this, David’s men turned on him and began to speak of stoning him. I’m beginning to feel things aren’t so bad in my life right now.
 
Then David reminded himself who he was; he may have quoted Psalm 91 or 93, but he encouraged himself in The Lord. After seeking The Lord’s direction in prayer, The Lord spoke to David and told him to go and “recover all” (1 Sam.30:8) - and that’s precisely what David and his men did, they recovered all that was taken from them.

I believe the difference between those who live with an attitude of constant loss and hopelessness and those who overcome and recover all is the ability and will to encourage themselves in The Lord, then ask for His direction. It’s God’s will for us to “Prosper, as our soul prospers, and be in good health.”
3 John 2, “Beloved, I pray that in every way you may succeed and prosper and be in good health [physically], just as your soul prospers [spiritually] AMP.” David guarded his thoughts about his situation and saw better days, and we can, too, but we must be mindful of our minds.