We are to love one another, so that we may walk honestly toward them  -  1 Thessalonians 4:9-10

But as touching brotherly love ye need not that I write unto you: for ye yourselves are taught of God to love one another. And indeed ye do it toward all the brethren which are in all Macedonia: but we beseech you, brethren, that ye increase more and more;

Paul stated that the Thessalonians did not have to be told to love one another, as these believers had distinguished themselves as lovers of fellow believers. God had used both the Holy Spirit and other Christians to teach these believers about love for one another and Paul encouraged them to abound in love.