A.W. Pink emphasizes the power of prayer in his sermon based on Mark 11:24, urging believers to ask in accordance with God's revealed will and to expect answers with unwavering faith. He outlines three key aspects of effective prayer: ensuring requests align with Scripture, pleading God's promises, and maintaining an attitude of expectancy. Pink warns against the devil's attempts to sow doubt and encourages Christians to confidently approach God, knowing they have a friend in Christ who intercedes on their behalf. Ultimately, he stresses that true faith honors God and leads to divine responses.