Sayyiduna Mahmud bin al-Rabi' (may Allah be pleased with him) narrates that the eyesight of Sayyiduna Itban bin Malik (may Allah be pleased with him) went during the time of the Messenger of Allah (peace and blessings be upon him), so he said: O Messenger of Allah, I am unable to pray with you in your mosque, and I would like you to pray with me in my mosque so that I may follow you in prayer. So the Messenger of Allah (peace and blessings be upon him) came to him. Then (the people) mentioned Malik bin al-Dukhshum before the Messenger of Allah (peace and blessings be upon him) and said: He is the refuge and shelter of the hypocrites, to whom they turn for refuge, and their stronghold. The Messenger of Allah (peace and blessings be upon him) said: "Does he not testify that there is no true god but Allah and that Muhammad (peace and blessings be upon him) is His servant and Messenger?" They said: Yes, but there is no good in his testimony. He (peace and blessings be upon him) said: "No servant bears this testimony truthfully from his heart and dies in that state except that Allah makes him forbidden to the Fire."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 15137