Musannaf Ibn Abi Shayba 23:90

Yazid ibn Harun narrated to us, from Hisham al-Dastawa'i, from Yahya, from Abu Qilabah, from Abu al-Malih, from Ibn Buraydah, from the Prophet, may Allah bless him and grant him peace, who said: "Whoever leaves the 'Asr (afternoon) prayer, his deeds have become void."