A.B. Simpson's sermon 'Shamgar, Deborah and Barak' emphasizes the significance of faith and action in the face of adversity, drawing parallels between the biblical figures and the challenges of contemporary life. He highlights Shamgar's humble yet heroic victory using an ox-goad, illustrating that God can use ordinary people and their everyday tools for extraordinary purposes. Deborah's leadership alongside Barak showcases the vital role of women in ministry and the importance of mutual support in achieving God's will. Simpson warns against the dangers of neutrality and encourages believers to seize opportunities for service, reminding them that even small acts of faith can lead to significant outcomes. Ultimately, he calls for a commitment to stand with God in the ongoing spiritual battles of life.