The apostle Paul began this section with a challenge to a certain group of people. He described that as being “perfect”. The word translated as “perfect” means to be complete or of full age. He is addressing those who are saved and also walking in obedience to the Lord. The danger is for those who have been saved for awhile to become careless. The danger is to become arrogant and think that we have arrived. Sometimes the newborn Christian is more faithful to the Lord because they are more dependent upon Him.
Paul was assured that God has a way of fixing the divisions that develop between truly born again Christians. It is very easy to set up superficial markers of what it means to be growing in the Lord. That is specifically true for those on the outside looking in. Those who are saved and have been walking with the Lord need to be reminded that if we get off course, God is able to reveal our arrogance to us. He chastens His children.

Hebrews 12:6 For whom the Lord loveth he chasteneth, and scourgeth every son whom he receiveth.
7 If ye endure chastening, God dealeth with you as with sons; for what son is he whom the father chasteneth not?
8 But if ye be without chastisement, whereof all are partakers, then are ye bastards, and not sons.

Those who are saved do not need to wait for the Lord to chasten us. The Holy Spirit will reveal sin in our lives from the moment we sin. We need to listen to Him.
In verse 16 Paul challenged those who were perfect that they should walk by the same rule. God has one rule for all His saints. There is a unity that can be built and must be built among God’s children. The way to build that unity is by pressing toward the mark. It is not by compromise. We need to be seeking to know the mind of Christ more. We need to desire that intimacy with Christ that Paul spoke of earlier in this passage.
In verse 17 Paul again reminded the recipients that they were brethren. They had a common God and Father and Saviour. That is the foundation upon which true saints build. We may like a certain colour better or some certain food better, but those things are superficial. What we need to build unity around is that true faith in the Lord Jesus Christ.
Paul stated that the saints needed to be followers together of him. He was the apostle. He was chosen of God for that position. Paul was not a false apostle. He is not telling them to follow him blindly. He has already established his authority. They could examine everything he said and did. They could know whether he was telling them the truth or whether he was leading them the right way. As these saints were following him, they were also to take note of others who were also following the same way.
Paul was not a one man show. He was not a cult leader. He was not trying to keep everyone for himself. He was not saying he was the only one who was worth following. He was saying that they needed to use him as a pattern by which they could examine others. As an apostle, he needed to be that example that was worthy of following. As the saints would look at others who made the same claim that Paul made earlier, they would see if they added up to the same life.
Christians need a standard to look to. We need someone that we can examine and see if we meet their standard.
The ultimate standard for any and every Christian is Jesus Christ. He is the foundation upon Whom every true believer must build. He chose twelve disciples whom He named apostles. An apostle was one chosen by Jesus Christ and sent out by Him. There are many false apostles today just as there were in the first century. We know the criteria for a true apostle. No one can meet that criteria today.
We can grow as we put our trust in the truth and build upon the truth.
Pastors today need to be careful in their teaching. I checked out another church yesterday that had made themselves known to me. I found them to be in the camp of those who are pressing toward being emergent, rather than pressing toward being Christlike.
The point that God is making here is that we need to build on the truth. The truth is not some personal interpretation of the Word of God. It is a submission to the Word of God and following God’s Word humbly and faithfully. Be willing to be examined in the light of God’s Word and if your walk is not in accordance with God’s Word, then get in line with what is right. If you are truly saved, that will not be a difficult thing to do. If you are a fraud, you will want to fight.
God’s Word is the standard.

Psalm 119:104 Through thy precepts I get understanding: therefore I hate every false way.