They spoke the truth. They are tormented, and their torment can be heard by all animals
Authentic hadithعن عائشة رضي الله عنها ، قالت: دخلت عليَّ عجوزان من عُجُز يهود المدينة، فَقَالَتا لي: إنَّ أهلَ القبور يُعذَّبون في قبورهم، فكذَّبتُهما، ولم أُنْعِم أنْ أُصَدِّقهما، فَخَرَجَتَا، ودخل عليَّ النبي صلى الله عليه وسلم ، فقلت له: يا رسول الله، إنَّ عجوزين، وذكرتُ له، فقال: «صَدَقَتَا، إنَّهم يُعذَّبون عذابًا تَسْمَعُه البهائم كلُّها» فما رأيتُه بعْدُ في صلاة إلا تعوَّذ من عذاب القبر.
‘Ā’ishah (may Allah be pleased with her) reported: There came to me two old women from the old Jewesses of Madīnah and said: "The grave dwellers are tormented in their graves." I did not believe them and I did not deem it proper to believe them. They went away and the Messenger of Allah (may Allah’s peace and blessings be upon him) came to me and I said to him: "O Messenger of Allah, there came to me two old women", and I mentioned to him what they had said. The Prophet (may Allah's peace and blessings be upon him) said: "They spoke the truth. They are tormented, and their torment can be heard by all animals." Never did I see him afterwards in prayer except that he would seek refuge (in Allah) from the torment of the grave.
Explanation
Two old Jewesses from Madīnah entered the place of ‘Ā’ishah (may Allah be pleased with her) and told her that the dead are punished in their graves. ‘Ā’ishah denied what they said and refused to believe them, for she did not like to believe the Jews who are known for lying, religious fabrications, and distortion of the Scripture. After these two Jewesses had departed, the Prophet (may Allah's peace and blessings be upon him) came and ‘Ā’ishah informed him of what they said. In response, he said: “They spoke the truth", for the dead are subject to torture that all animals can hear. Then, ‘Ā’ishah went on to inform us that she never saw the Prophet (may Allah's peace and blessings be upon him) ever since offer a prayer without seeking refuge from the punishment of the grave.
Source · Narrated by Bukhari & Muslim
From the Hadith Encyclopedia (hadeethenc.com).