أُولَئِكَ الَّذِينَ يَعْلَمُ اللَّهُ مَا فِي قُلُوبِهِمْ فَأَعْرِضْ عَنْهُمْ وَعِظْهُمْ وَقُل لَّهُمْ فِي أَنفُسِهِمْ قَوْلًا بَلِيغًا
They are the ones whom Allah knows as to what is in their hearts. So let them alone, and advise them, and speak to them concerning themselves far-reaching words.
Agha Ali Puya Commentary
Commentary on Quran 4:63
[Pooya/Ali Commentary 4:63] Qawlan baligha means effective, chaste, rational, impressive and penetrating arguments.