It is narrated from Sayyiduna Abu Bakr (may Allah be pleased with him) that the Prophet (peace and blessings of Allah be upon him) said: "There is no sin more deserving than oppression and severing of ties of kinship for which the doer is punished quickly in this world, and also faces punishment in the Hereafter."
Hadith Referenceالادب المفرد / كتاب الوالدين / 29
Hadith Gradingالألبانی:صحیح
Hadith Takhrij«صحيح : أخرجه أبوداؤد، الأدب، باب النهي عن البغي : 4902 و الترمذي : 2511 و ابن ماجه : 4211 ، الصحيحة : 918، 978»
Sayyiduna Imran bin Husain (may Allah be pleased with them both) narrates that the Messenger of Allah (peace and blessings be upon him) said: "What do you say about adultery, drinking wine, and theft?" We said: Allah and His Messenger know best. He (peace be upon him) said: "They are extremely evil and lowly deeds, and there are prescribed punishments for them." (And) "Shall I not inform you about the gravest of sins?" (He said they are:) "Associating partners with Allah the Exalted, and disobedience to parents." He was reclining, then he sat up straight and said: "And lying (is also a very great sin)."
Hadith Referenceالادب المفرد / كتاب الوالدين / 30
Hadith Gradingالألبانی:ضعیف
Hadith Takhrij«ضعيف : رواه المروزي فى البر والصلة : 105 و الطبراني فى الكبير : 140/18 و البيهقي فى الكبرىٰ : 209/8 ، غاية المرام : 277»