Surah Al-Hijr 15:99

وَٱعْبُدْ رَبَّكَ حَتَّىٰ يَأْتِيَكَ ٱلْيَقِينُ

And worship your Lord until there comes to you the certainty [i.e., death].

Translation: Saheeh International

Tafsir

and worship your Lord until Certainty — Death — comes to you.

Excerpt from Tafsir al-Jalalayn, commentary on 15:99, via Quran.com. The reader has the full commentary and 9 more tafsirs.