" Let’s think back for a moment to the boring sermon. Sometimes the sermon we hear is boring because it went on for too long (or it was not long enough) to engage the listeners. One of the most culturally sensitive areas of human life is this area of time. What various people and cultures consider “late” and “too long” varies widely. In the United States, African-American and Hispanic Christians have services in which singing, prayer, and preaching go on at least 50 percent longer than the attention spans and comfort zones of most Anglo people. Anyone who leads worship services will, then, unavoidably be contextualizing toward some people and away from others. "

― Timothy J. Keller , Center Church: Doing Balanced, Gospel-Centered Ministry in Your City