The Messenger of Allah ﷺ said, "On the night I was taken on the night journey, I passed by Musa at the red sand dune, and he was standing in his grave, praying."
أن رسول الله ﷺ قال: أتيت على موسى عليه السلام ليلة أسري بي عند الكثيب الأحمر، وهو قائم يصلي في قبره.
Reported by Muslim in the Virtues chapter (2375:165) through various routes from Hammad bin Salama, from Thabit Bunani and Sulayman Taymi, from Anas bin Malik, and he related it.His statement, "while he was standing praying in his grave," should be understood as referring to the life of the barzakh, not worldly life.