Tafsir of Al Imran 3:143

You did indeed wish for death (martyrdom) before you met it. Now you have seen it openly with your own eyes. The Ayah proclaims, O believers! Before today, you wished that you could meet the enemy and were eager to fight them. What you wished has occurred, so fight them and be patient. In the Two Sahihs it is recorded that the Messenger of Allah said,

ﻻ تتمنوا لقاء العدو وسلوا الله العافية فٳذا لقيتموهم فاصبروا واعلموا أن الجنة تحت ظﻼل السيوف

Do not wish to encounter the enemy, and ask Allah for your well-being. However, if you do encounter them, then observe patience and know that Paradise is under the shade of swords. This is why Allah said here,

فقد رأيتموه

(Now you have seen it): death, you saw it when the swords appeared, the blades were sharpened, the spears crisscrossed and men stood in lines for battle. This part of the Ayah contains a figure of speech that mentions imagining what can be felt but not seen