Dr. Mark Durie writes at Answering Islam:

‘Isa the destroyer of Christianity

The prophet ‘Isa will have an important role in the end times, establishing Islam and making war until he destroys all religions save Islam. He shall kill the Evil One (Dajjal), an apocalyptic anti-Christ figure.

In one tradition of Muhammad we read that no further prophets will come to earth until ‘Isa returns as ‘a man of medium height, or reddish complexion, wearing two light garments, looking as if drops were falling down from his head although it will not be wet. He will fight for the cause of Islam. He will break the cross, kill pigs, and abolish the poll-tax. Allah will destroy all religions except Islam. He (‘Isa) will destroy the Evil One and will live on the earth for forty years and then he will die’. (Sunan Abu Dawud, 37:4310) The Sahih Muslim has a variant of this tradition: ‘The son of Mary ... will soon descend among you as a just judge. He will ... abolish the poll-tax, and the wealth will pour forth to such an extent that no one will accept charitable gifts.’ (Sahih Muslim 287)

What do these sayings mean? The cross is a symbol of Christianity. Breaking crosses means abolishing Christianity. Pigs are associated with Christians. Killing them is another way of speaking of the destruction of Christianity. Under Islamic law the poll-tax buys the protection of the lives and property of conquered ‘people of the Book’. (At-Taubah 9:29) The abolition of the poll-tax means jihad is restarted against Christians (and Jews) living under Islam, who should convert to Islam, or else be killed or enslaved. The abundance of wealth refers to booty flowing to the Muslims from this conquest. This is what the Muslim ‘Isa will do when he returns in the last days.

Muslim jurists confirm these interpretations: consider, for example, the ruling of Ahmad ibn Naqib al-Misri (d. 1368).

"... the time and the place for [the poll tax] is before the final descent of Jesus (upon whom be peace). After his final coming, nothing but Islam will be accepted from them, for taking the poll tax is only effective until Jesus' descent (upon him and our Prophet be peace) ..." (The Reliance of the Traveller. Trans. Nuh Ha Mim Keller, p. 603).

Ibn Naqib goes on to state that when Jesus returns, he will rule ‘as a follower’ of Muhammad.