Musnad Abi Ya'la 1351 — he said: I heard the Messenger of Allah ﷺ

It is narrated from Sayyiduna Abu Sa'id al-Khudri (may Allah be pleased with him) that he said: I heard the Messenger of Allah (peace and blessings be upon him) saying: "Gog and Magog will be let loose upon the people (after the wall breaks), as Allah Almighty says: 'And they will descend swiftly from every elevation.' They will overwhelm the people, and the Muslims, out of fear of them, will shut themselves up in their cities and fortresses and will also gather their livestock with them (in safe places). They will drink up the water of the earth, so much so that a group of them will pass by a river and drink all its water, leaving it dry; then those who come after them will pass by there and say: 'There used to be water here once.' When no one (to face them) is left on earth except those shut up in fortresses, their spokesman (of Gog and Magog) will say: 'These people of the earth are finished; now the people of heaven are left.' Then one of them will brandish his spear and hurl it towards the sky, and it will come back to him soaked in blood, as a trial and a test. While they are in this state, Allah Almighty will create a worm (naghaf) in their necks, like the worm found in the neck of a locust, as a result of which they will all perish together and not a sound will be heard from them. Then the Muslims will say: 'Is there not a man of courage who will risk his life for us and go and see what state the enemy is in?' So a man from among them will go out, hoping for reward from Allah and firmly resolved to sacrifice his life, and he will find them all lying dead on top of one another. Then he will call out: 'O company of Muslims! Rejoice, for Allah Almighty has sufficed you against your enemy.' So the people will come out of their cities and fortresses and let their animals out to graze, but there will be no fodder for those animals except their flesh, and those animals (eating that flesh) will grow fatter than they ever had from eating the best pasture."