Is there Room for Lukewarm Christians in God's Kingdom?

Many people teach a difference between Christian disciples and Christians who have accepted Jesus as their Saviour. Most “believers” prefer to stay at home, raise funds, and pray for the “disciples"… storm troopers who take the message into all the world. What is a Christian? Do true Christians have a choice? Did Jesus have a category for neutrals, who are still undecided in the struggle between Christians vs non-Christians?