First, you serve God in your marriage by loving Him. Your service is the exercising of vows you promised to keep in His presence to your spouse. Every time you pray for your spouse and with your spouse you are engaged in ministry. 

Second, you serve your spouse by also loving him or her. Your actions toward your spouse such as listening to them when they want to talk, supporting them in their dreams or careers and just being there are a few examples of service.  Another more fun way you serve your spouse is through intimacy. The closeness between husband and wife strengthens the relationship and establishes trust.  

Trusting your spouse is a necessary service for the marriage.

Next, you serve others by being an example to other couples and singles that want to get married.  

Your marriage will minister in a positive or negative way to others depending on how you conduct yourself.  

Finally, you minister to yourself by being the best husband or wife you know how to be. Doing your part to keep your marriage strong can bring satisfaction and enjoyment. Marriage is one of the best ministries to have because you are in a position to encourage and uplift others.