It has been wondered among believers what the obedient Christian looks like--can we spot them? Jesus said that if we love Him we will obey His commandments (cf. John 14:21). Obedience is the only test of faith according to John MacArthur, and can be distinguished but not separated from it, as they are equated and correlated in Heb. 3:17-18; Rom. 1:5; 16:26; Acts 6:7, and John 3:36. Dietrich Bonhoeffer said eloquently: "Only he who believes is obedient, and only he who is obedient believes." In Acts 5:32 it says that the Holy Spirit is given to those who obey Him.
There is no such thing as a disobedient Christian as a subclass or rank of Christian, though Christians can and do disobey God and sin both willingly and unintentionally. We never reach a point of entire sanctification or perfectionism as Wesleyans and Deeper Life or Keswick movement people like to call it, because if we deny we have sinned we make Him a liar and His word is not in us according to 1 John 1:10. Also, Proverbs 20:9 (ESV) says, "Who can say, 'I have made my heart pure, I am clean from my sin?'" The psalmist said he'd seen the limit of all perfection in Psalm 119:96.
We are not fruit inspectors of each other's fruit but should examine ourselves carefully to see whether we are walking in the faith--don't break faith! In other words, we should be too busy in our walk with the Lord to wonder about our brother's walk and whether he is obedient. We should search our own hearts and examine our own fruits. The Spirit-filled life exhibits the fruit of the Spirit in increasing bounty as one matures because fruits are grown and if we abide in Christ they are a natural result.
The reason we obey God is that we are His creatures and it is fitting and proper as we owe Him this. We don't feel we have to as believers but want to or get to. God alone is worthy of our obeisance and homage. God's commandments are not burdensome (cf. 1 John 5:3) and we do them "in love." To love Him is to obey Him! The Bible was given to shed light on God's will and as believers, we naturally seek God's will in our lives as a matter of His lordship. All sin is disobedience according to Scripture, and we become more godly and less sin-prone as we mature in Christ. God's Word gives us instruction in righteousness. Bear in mind that it is God's Spirit living in us that gives us the power to overcome sin and obey Christ and become Christlike--we cannot do it on our own (the Christian life is not hard, it's impossible!). God's commandments are for our own good and He knows what is best for us. We must not rely on the energy of the flesh, but learn that He gives us the power in the Spirit--we don't have the freedom to live in the flesh, but the power to live in the Spirit.
The Navigators taught me a great truth: The obedient Christian is regularly involved in prayer, getting into Bible study and reading, fellowship and worship, and witness and outreach. We have both a ministry to our brothers and a mission to the unsaved in our obedience. There are Lone Ranger Christians who navigate solo and think they don't need the body--if you love Jesus, you will love His body! We must be "rooted and grounded" in the body of Christ and in the truth to have discernment and growth and move forward in our walk. It is absolutely impossible to be living in obedience apart from the discipline, nurture, discipleship, and fellowship of the body of Christ! We all need each other and no one, no matter how gifted, has all the gifts and doesn't need the other members of the body.
Furthermore, obedience not only implicates obedience to the Word per se, but to all dully delegated authority or "the powers that be" in Paul's lingo. A Christian must obey the law unless it is in clear contradiction to the Word. He is a good and upright or model citizen who not only exercises his rights but does his responsibilities. To obey authority also means parental and any authority in loco Dei or in the place of God, even an institution. The government is a God-ordained institution, just like the church and the family--but family is the premier authority and most important one to be protected. Another aspect of obedience is submission to one another in the name of Christ, and not lording it over others, for instance, but allowing Christ to rule in His body, the church. The final aspect of obedience that must take place is accountability because if one is a rogue all on his own and doing his own thing he is out of fellowship with Christ and disobedient to direct commands. Every believer needs accountability and is accountable, whether it is to his suiting or not.
In my personal walk, obedience is how I relate to the leading of the Holy Spirit as I walk in the Spirit and walk by faith and not by sight (cf. 2 Cor. 5:7). Paul said, "As many as are led by the Spirit are sons of God." The goal is to know Christ through the body and, our walk and make Him known by our testimony, witness, and mission. When I read the Word I get "Aha!" moments where I feel God speaking to me or me of something convicting, which you might call an existential experience--you can experience God in the Word and He has promised to use it to speak to us. I obey Christ by submitting to authority and not trying to make up my own rules and do my own thing like Israel was doing in Judges 21:25 ("each man did what was right in their own eyes...").
I believe prayer is the acid or litmus test of the believer and a true gauge of his pursuit of holiness and fellowship with God. Fellowship is another test to consider: '"If we walk in the light, as he is in the light, we have fellowship with one another ..." (1 John 1:7, ESV). God has put me in the ministry of doing a Bible study and I am being obedient by preparing and studying for that--when God considers us faithful, He puts us into the ministry. I also obey God by abiding (or staying in fellowship by having no unconfessed or unjudged sin) in Christ and being sensitive to the Spirit so as not to quench or grieve the Spirit I am ready to witness of my faith in obedience and look for open doors from God at all times and thank God for every opportunity that He gives me to share my faith in observance of the Great Commission. In short, I have heard it expressed very well: A great Christian has a great commitment to the Great Commission and the Great Commandment! There are many commandments in the Bible as well as prohibitions, but basically, we become a natural as we go on to know the Lord and walk with Him in faith and fellowship. Soli Deo Gloria!