A.B. Simpson emphasizes the urgency of the missionary call, likening it to life-and-death emergencies that demand immediate action. He highlights the dire spiritual needs of humanity, the vast number of souls yet unreached, and the swift passage of time as reasons for Christians to actively engage in evangelism. Simpson calls for a courageous response to the open doors for spreading the Gospel, urging believers to 'redeem the time' and fulfill their obligation to share Christ with the world. He warns that the opportunity for evangelization may close if not acted upon swiftly, and he encourages steadfastness in the face of opposition. Ultimately, he inspires a sense of responsibility and urgency in the mission of the Church.