Sayyiduna Abdullah bin Amr (may Allah be pleased with them both) narrates that the Prophet (peace and blessings be upon him) said: "By Him in Whose hand is my soul, the killing of a believer is greater in the sight of Allah on the Day of Resurrection than the destruction of the entire world."
Hadith Referenceمعجم صغير للطبراني / كتاب الحدود / 926
Hadith Gradingمحدثین:صحيح
Hadith Takhrij«صحيح ، أخرجه النسائي فى «المجتبیٰ» برقم: 3987 ، قال الشيخ الألباني: صحيح ، والنسائي فى «الكبریٰ» برقم: 3434، والترمذي فى «جامعه» برقم: 1395، والبيهقي فى«سننه الكبير» برقم: 15972، 15973، والبزار فى «مسنده» برقم: 2393، والطبراني فى«الكبير» برقم: 14256، 14369، والطبراني فى «الأوسط» برقم: 4349، والطبراني فى «الصغير» برقم: 594، وابن أبى شيبة فى «مصنفه» برقم: 28328»
´It was narrated that 'Abdullah bin 'Amr bin Al-'As said:` "The Messenger of Allah [SAW] said: 'By the One in Whose Hand is my soul, killing a believer is more grievous before Allah than the extinction of the whole world.'"
Hafiz Muhammad Ameen
That is, if the world is hypothetically assumed to be without believers, then the destruction of the world and all that is in it is lighter in the sight of Allah Ta'ala than the unjust loss of the life of a single believer. Or, if, hypothetically, the entire world—which is assumed to be devoid of believers—is destroyed, then its sin is much less than the sin of the unjust killing of a single believer. The purpose is to demonstrate the importance of the believer and of faith, which has been illustrated through this hypothetical scenario. This style is common in customary usage.
Source: Sunan Nasa'i: Translation and Benefits by Shaykh Hafiz Muhammad Amin Hafizullah, Page: 3991