“ The things ” that Paul mentioned are Bible truths that moved Timothy to put faith in the good news.
وَهٰذِهِ ٱلْحَقَائِقُ كَانَ لَهَا ٱلتَّأْثِيرُ عَيْنُهُ فِينَا ،‏ وَهِيَ لَا تَزَالُ تُسَاعِدُنَا أَنْ نَبْقَى ‹ حُكَمَاءَ لِلْخَلَاصِ › .‏