Mike Bickle emphasizes David's courage and resolve during his time in Keilah, despite facing overwhelming shame, fear, and despair from past failures and current pressures. David's willingness to inquire of the Lord and engage in battle for the people of Keilah, even when his own men were afraid, showcases his leadership and commitment to God's purposes. Through his struggles, David learns that investing in others can lead to personal healing and breakthrough, as he finds strength in helping those in need. The sermon highlights the importance of stepping out of comfort zones and trusting God in challenging circumstances, as well as the power of encouragement and support from friends like Jonathan.