It is narrated from Sayyiduna Ibn Mas'ud (may Allah be pleased with him) that once I prayed with the Prophet (peace and blessings of Allah be upon him) at night. The Prophet (peace and blessings of Allah be upon him) stood for so long that I began to intend something bad in my heart. His students asked: What did you intend? He replied: That I would sit down and leave the Prophet (peace and blessings of Allah be upon him) standing.
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 4199