Some of Jesus’ disciples were married. Marriage and singleness both offer unique capacities to serve God.
At least some of Jesus’ disciples, like Peter, were married. This suggests that church leaders and workers today are biblically permitted to marry, as evidenced by passages in 1 Timothy and Titus that discuss marital qualifications for elders and deacons. Marriage is seen as a reflection of Christ's relationship with the church and provides mutual support, while singleness allows for a focused dedication to God's kingdom. Regardless of marital status, Christians are called to depend on God and serve Him faithfully.
Seeing that at least some of the disciples were married, it's fairly simple to conclude that ministers, pastors, missionaries, and other church leaders and workers are allowed by the Bible to be married. The qualifications for elders and deacons include references to their marriages and families (1 Timothy 3:1–13; Titus 1:5–9). These qualifications do not require that church leaders be married, but they demonstrate that they can be.
Christians can serve God in any life situation (1 Corinthians 7:17–24). Marriage is a reflection of Christ's relationship with the church (Ephesians 5:22–33). God instituted marriage in the garden of Eden, and it is a good thing (Genesis 2:24–25). The marriage relationship can provide support, encouragement, and a depth of relationship that allows each person in the marriage, both individually and as a couple, to serve the Lord. At the same time, singleness points to eternity, when "the marriage of the Lamb has come, and his Bride has made herself ready" (Revelation 19:7) (see also Matthew 22:30). In singleness, a person might be more directly focused on God's kingdom (1 Corinthians 7:32–35). Singleness can also provide unique opportunity to rely on God for relational intimacy and offer different ways of demonstrating the reality that believers, together, are the family of God. Both situations, of course, have unique struggles and hardships. No matter our current life situation, we are called to depend on God and faithfully follow Him. We can follow and serve God wholeheartedly, whether we are married or single.