1 Thessalonians 4:9

But concerning love of the brethren ye have no need that one write unto you: for ye yourselves are taught of God to love one another;

Love of the brethren ... love one another ... Paul's use of the word [@filadelfia] here, meaning love in the natural brotherly sense of affection that is natural among families, and used even of affection among animals, seems to suggest the word "instinctively"; for it is God who instills all instinctive qualities in man and beast. Nor does the statement "taught of God to love one another" deny this. If, on the other hand, Paul meant the love which he and his fellow-laborers had taught the Thessalonians, that too, in the ultimate sense, is being "taught of God." It will be remembered when Peter confessed that Jesus is "the Christ the Son of the living God" (Matthew 16:16), a truth Peter had been taught personally by Jesus himself, that the Lord promptly declared, "Flesh and blood hath not revealed it unto thee, but my Father who is in heaven."

In any case, Paul here admitted that the Thessalonians were in full possession of the grace of loving one another. Would that all churches were so.