Final answer:
The 'bride of Christ' metaphor for the church primarily illustrates the church's purity and intimate relationship with Christ, emphasizing the sanctity of this spiritual union. So ,the correct option is b) the church's purity and intimacy with Christ.
Step-by-step explanation:
The biblical image of the church as "the bride of Christ" helps illustrate the church's purity and intimacy with Christ. This image signifies a close and sanctified relationship, much like that of a bride and her groom, emphasizing the spiritual union and love between Christ and the church. The church is seen as consecrated and set apart for a special, intimate relationship with Jesus, affirming its holiness and its role in the spiritual lives of believers. By contrast, the 'bride' metaphor does not directly reflect the church's authority, hierarchy, or role as a servant, although these can be interconnected aspects within the broader theology of the church.