Surah Taha 20:115

وَلَقَدْ عَهِدْنَآ إِلَىٰٓ ءَادَمَ مِن قَبْلُ فَنَسِىَ وَلَمْ نَجِدْ لَهُۥ عَزْمًا

And We had already taken a promise from Adam before, but he forgot; and We found not in him determination.

Translation: Saheeh International

Tafsir

And We made a covenant with Adam We enjoined him not to eat of the tree before that is before he ate of it but he forgot he disregarded Our covenant and We did not find in him any constancy any resoluteness or patience in abiding by what We forbade him from.

Excerpt from Tafsir al-Jalalayn, commentary on 20:115, via Quran.com. The reader has the full commentary and 9 more tafsirs.