Now he reminds them to press on in those commandments. When Paul did his missionary work he not only won converts and baptized. He also followed the mandate of the great commission to teach them to observe whatsoever the Lord Jesus had commanded. God's word and God's will are in these instructions. And his will for believers is that their sanctification.
Sanctification is the process of becoming holy.
May the Lord make you increase and abound in love to one another and to all men, as we do to you, so that he may establish your hearts unblamable in holiness before our God. If abounding in love is the means by which our hearts are established in holiness , then love must be the thing Paul has in mind when he exhorts us to make progress in holiness or sanctification. The specific application of love in view here in our text is abstaining from sexual immorality. Abounding in love for all men is incompatible with sexual promiscuity. Instead they should take their own wives.