It is narrated from Sayyiduna Abu al-Darda' (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "The believer continues to press ahead in goodness and remain at ease so long as he is not involved in unlawful bloodshed; then when he sheds unlawful blood, he becomes exhausted and loses heart."
Imam al-Tabarani (may Allah have mercy on him) said: "No one narrated these two hadiths from Abdullah bin Abi Zakariyya except Khalid bin Dihqan, and Muhammad bin Shu'ayb is alone in narrating them both."
Hadith Referenceالمعجم الأوسط / باب النون / 9229
Hadith Takhrij«أخرجه البيهقي فى «السنن الكبرى» برقم: 15965، والطبراني فى «الصغير» برقم: 1108»