Al-Matalib al-'Aliyah 4534 — The trial of the grave and the punishment

Abdullah al-Danaj narrates: I was present with Sayyiduna Anas bin Malik (may Allah be pleased with him) when a man said to him: "O Abu Hamzah! Some people deny the intercession (on the Day of Resurrection) (and reject it)." He (may Allah be pleased with him) said: "Do not sit with them (that is, do not keep their company)." Then the man said (again): "Some people also deny the punishment of the grave." He (may Allah be pleased with him) said (the same again): "Do not sit with them."
This report is sahih (authentic), and it contains a strong emphasis on avoiding the company of those misguided people who deny established articles of faith such as the intercession and the punishment of the grave.