John MacArthur @ http://www.sfpulpit.com outline three characteristics of a good "soldier for Christ". He notes:The first mark of a good soldier is the willingness to suffer hardship with the rest of the soldiers.
You have been called to endure hardship, and every Christian who has gone before you has had his share. And although you haven’t yet shed blood for your faith (Hebrews 12:4), you will experience hardship as a Christian for your faithfulness–count on it. Jesus said, “If they persecuted Me, they will also persecute you” (John 15:20). But be encouraged for He also said, “In the world you have tribulation, but take courage; I have overcome the world” (John 16:33). Jesus is the perfect Commander who leads by example and will bring you to certain victory in the end.
Secondly, a good soldier is marked by his separation from the “normal” life.
Just as the dutiful soldier places his life willingly on the line in the service of his commander, so also will you, as a faithful Christian, willingly deny yourself, take up your cross, and follow Christ (Luke 9:23). And you will find yourself echoing Paul’s words: “I do not consider my life of any account as dear to myself, in order that I may finish my course, and the ministry which I received from the Lord Jesus” (Acts 20:24).
The final mark of a good soldier is a genuine desire to “please the one who enlisted him as a soldier.”
The Christian’s greatest desire is to please Christ, and his fondest hope is to be rewarded for faithful service, to hear his Master say, “Well done, good and faithful slave; you were faithful with a few things, I will put you in charge of many things, enter into the joy of your master” (Matthew 25:21). With that hope in the forefront of your mind, let your life be animated and driven forward by your love for Jesus Christ. And make it your ambition, “whether at home or absent, to be pleasing to Him” (2 Corinthians 5:9) — He is your spiritual Commander-in-Chief.