All conflicts and disagreements will end in the time of Hazrat Mahdi (as)

The (competents of) battle will abandon its load (arms and equipment). (Sunan Ibn Majah, 10/334)

Earth will be filled with peace, just as a bowl is filled with water. No enmity will remain between anyone. All enmity, conflict, and disagreement will surely vanish. (Sahih Muslim, 1/136)

(The competents of) War will abandon its load (namely, arms and the like). (Al-Sharani, Mukhtasar Tazkirah al-Qurtubi, p. 496)

He will do away with enmity and hatred. The venom will be removed from poisonous animals. Even a small boy will place his hand in a serpent’s mouth, and the serpent will not harm him. The wolf will be like a dog in a herd of sheep or goats. (Sunan Ibn Majah, p. 331-35)

In his time, the wolf will play with the sheep and snakes will not harm children. A person will sow a handful of seed and will receive back 700 handfuls of grain. (Ibn Hajar al-Haythami, Al-Qawl al-Mukhtasar fi `Alamat al-Mahdi al-Muntadhar, p. 43)