VERSE 15. But if ye bite and devour one another take heed that ye be not consumed one of another.
When faith in Christ is overthrown peace and unity come to an end in the church. Diverse opinions and dissensions about doctrine and life spring up, and one member bites and devours the other, i.e., they condemn each other until they are consumed. To this the Scriptures and the experience of all times bear witness. The many sects at present have come into being because one sect condemns the other. When the unity of the spirit has been lost there can be no agreement in doctrine or life. New errors must appear without measure and without end.
For the avoidance of discord Paul lays down the principle: "Let every person do his duty in the station of life into which God has called him. No person is to vaunt himself above others or find fault with the efforts of others while lauding his own. Let everybody serve in love."
It is not an easy matter to teach faith without works, and still to require works. Unless the ministers of Christ are wise in handling the mysteries of God and rightly divide the word, faith and good works may easily be confused. Both the doctrine of faith and the doctrine of good works must be diligently taught, and yet in such a way that both the doctrines stay within their God-given sphere. If we only teach works, as our opponents do, we shall lose the faith. If we only teach faith people will come to think that good works are superfluous.
VERSE 16. This I say then, Walk in the Spirit, and ye shall not fulfill the lust of the flesh.
"I have not forgotten what I told you about faith in the first part of my letter. Because I exhort you to mutual love you are not to think that I have gone back on my teaching of justification by faith alone. I am still of the same opinion. To remove every possibility for misunderstanding I have added this explanatory note: 'Walk in the Spirit, and ye shall not fulfill the lust of the flesh.'"
With this verse Paul explains how he wants this sentence to be understood: "By love serve one another. When I bid you to love one another, this is what I mean and require, 'Walk in the Spirit.' I know very well you will not fulfill the Law, because you are sinners as long as you live. Nevertheless, you should endeavor to walk in the spirit," i.e., fight against the flesh and follow the lead of the Holy Ghost.
It is quite apparent that Paul had not forgotten the doctrine of justification, for in bidding the Galatians to walk in the Spirit he at the same time denies that good works can justify. "When I speak of the fulfilling of the Law I do not mean to say that you are justified by the Law. All I mean to say is that you should take the Spirit for your guide and resist the flesh. That is the most you shall ever be able to do. Obey the Spirit and fight against the flesh."
VERSE 16. And ye shall not fulfill the lust of the flesh.
The lust of the flesh is not altogether extinct in us. It rises up again and again and wrestles with the Spirit. No flesh, not even that of the true believer, is so completely under the influence of the Spirit that it will not bite or devour, or at least neglect, the commandment of love. At the slightest provocation it flares up, demands to be revenged, and hates a neighbor like an enemy, or at least does not love him as much as he ought to be loved.