Abu Bakr bin 'Ayyash al-Asadi أبو بكر بن عياش بن سالم الأسدي · The Book of the Prayer

"We were with the Messenger of Allah on a campaign, and he said: 'Hasten to perform prayer on a cloudy day, for whoever misses the 'Asr prayer, all his good deeds will be in vain.'"