Surah Al-Baqarah 2:154

وَلَا تَقُولُوا۟ لِمَن يُقْتَلُ فِى سَبِيلِ ٱللَّهِ أَمْوَٰتٌۢ ۚ بَلْ أَحْيَآءٌ وَلَـٰكِن لَّا تَشْعُرُونَ

And do not say about those who are killed in the way of Allāh, "They are dead." Rather, they are alive, but you perceive [it] not.

Translation: Saheeh International

Tafsir

And say not of those slain in God’s way that ‘They are dead’; rather they are living their spirits are according to a hadīth contained in green birds that take wing freely wherever they wish in Paradise; but you are not aware but you do not know their condition.

Excerpt from Tafsir al-Jalalayn, commentary on 2:154, via Quran.com. The reader has the full commentary and 9 more tafsirs.