Hadith: I prayed one night with the Prophet (may Allah's peace and blessings be upon him) and he prolonged the standing for so long that I was I about to do something bad. It was asked: “What were you about to do?” He said: “I was about to sit down and leave him (standing).”

عن ابن مسعود رضي الله عنه قال: صليت مع النبي صلى الله عليه وسلم ليلة، فأطال القيام حتى هَمَمْتُ بأمْرِ سُوءٍ! قيل: وما هَمَمْتَ به؟ قال: هَمَمْتُ أن أجلس وأَدَعَه.
[صحيح] - [متفق عليه]

Ibn Mas‘ūd (may Allah be pleased with him) reported: I prayed one night with the Prophet (may Allah's peace and blessings be upon him) and he continued standing for long until I was I about to do something bad. Someone said: What were you about to do? He said: I was about to sit down and leave him (standing).
[Authentic hadith] - [Narrated by Bukhari & Muslim]

Explanation

Ibn Mas‘ūd (may Allah be pleased with him) reported: I prayed one night with the Prophet (may Allah's peace and blessings be upon him) and he prolonged the standing for so long that I was I about to do something bad. It was asked: "What were you about to do?" He said: "I was about to sit down and leave him (standing)."