John’s reason for writing to Gaius was not just to thank him. John also wanted to help him deal with a serious problem.
وَقَدْ كَتَبَ يُوحَنَّا بِهٰذَا ٱلْخُصُوصِ :‏ « نَحْنُ مُلْزَمُونَ بِأَنْ نُضِيفَ أَمْثَالَ هٰؤُلَاءِ ،‏ لِنَصِيرَ رُفَقَاءَ فِي ٱلْعَمَلِ فِي ٱلْحَقِّ » .‏ —‏ ٣ يو ٨‏ .‏