Example in the Quran

وَلِيَعۡلَمَ ٱلَّذِينَ نَافَقُواْۚ وَقِيلَ لَهُمۡ تَعَالَوۡاْ قَٰتِلُواْ فِي سَبِيلِ ٱللَّهِ أَوِ ٱدۡفَعُواْۖ قَالُواْ لَوۡ نَعۡلَمُ قِتَالٗا لَّٱتَّبَعۡنَٰكُمۡۗ هُمۡ لِلۡكُفۡرِ يَوۡمَئِذٍ أَقۡرَبُ مِنۡهُمۡ لِلۡإِيمَٰنِۚ يَقُولُونَ بِأَفۡوَٰهِهِم مَّا لَيۡسَ فِي قُلُوبِهِمۡۚ وَٱللَّهُ أَعۡلَمُ بِمَا يَكۡتُمُونَ

and expose the hypocrites. When it was said to them, “Come fight in the cause of Allah or ˹at least˺ defend yourselves,” they replied, “If we had known there was fighting, we would have definitely gone with you.” They were closer to disbelief than to belief on that day—for saying with their mouths what was not in their hearts. Allah is All-Knowing of what they hide.