The Promised Messiah(as) says:
The second key sign is that when that Promised Messiah will come he shall break the Cross, kill the swine and kill the one-eyed Dajjal. Every disbeliever who is touched by his breath will die instantly. The real interpretation of this special aspect is that the Messiah on arriving in this world will crush under his feet all the glory of the religion of the Cross, and that he shall destroy with the weapon of decisive arguments those who are afflicted with shamelessness and immodesty like swine, and who devour filth like pigs, and that he will wipe out with the sword of clear proofs the opposition of those who possess only worldly insight and are bereft of the eye of faith in place of which they have only an unsightly taint.
So these are the arguments with which the vanquishing is to be done so that the existence of their false claims can be finished off.
The Promised Messiah(as) further says:
Not only such one-eyed people, but also every disbeliever who contemptuously looks down at Islam, will suffer spiritual extinction through the glorious breath of Messianic reasoning.
The Promised Messiah(as) will come and defeat them with his reasoning.
In short, all these statements are metaphorical, which have been unfolded very well to this humble person. Some may or may not understand it now but after waiting for sometime, and despairing altogether of the hopes of their baseless expectations that they now entertain, all of them will be inclined to this direction. (Izala-e-Auham, Ruhani Khaza’in, vol 3, pp. 141-143 footnotes)
In short, the Promised Messiah(as) has challenged the Christians in this age. It was him alone who stopped Christianity in its tracks as it was spreading fast. At that time, in India, hundreds of thousands of Muslims were turning to Christianity. It was only the Promised Messiah(as) who not only stopped their onslaught, rather also restored the honour of Islam. In addition, the Ahmadiyya Muslim Community has stopped the onslaught of Christianity in Africa; demonstrated the beautiful picture of Islam to them and converted thousands of Christians to Islam. These were the achievements of the Messiah that the Promised Messiah(as) displayed and, with the Grace of God, it is with his teaching and reasoning that today the Ahmadiyya Muslim Community is moving forward, winning the hearts, and Insha' Allah will keep on doing so. Just as the Promised Messiah(as) has said:
One day these people will be disillusioned, and then will return.
So this is the explanation of how the deceit of these people has to be ended. This is the meaning of killing the swine and breaking the Cross and the connotation of as contesting the explained. Dajjal that the Promised Messiah(as) has explained.
As I have said earlier, it is the Ahmadiyya Muslim Community alone that is contending with Christianity. Recently, there was a television programme on one of the TV channels (probably it was Geo or ARY channel, or some other similar Asian channel) in which one Allamah Dr. Asrar said that because the Muslim religious people were illiterate and their religious knowledge was non-existent, both of the Holy Qur’an and the Bible, whereas Mirza Ghulam Ahmad Qadiani was a scholarly man, and had knowledge of the Bible as well as of other religions, that is why he contended with the Christians and silenced them. His words (Dr. Asrar's) were to this effect. Anyway, he accepted that it was the Promised Messiah(as), who just as he himself has said, dismissed them with decisive arguments, strong arguments. They accept that it was Hadrat Mirza Ghulam Ahmad Qadiani alone who halted the onslaughts of Christianity at the time and saved the Muslims from converting to Christianity. He (Dr. Asrar) then went on to give some senseless explanations, different explanations, he spoke a little against the Promised Messiah(as) that he could not be the Messiah. In any case, it is acknowledged today that if anyone stood up to Christianity and dismissed their teachings with arguments, it was just one as champion, whose name is Mirza Ghulam Ahmad Qadiani.
Therefore, whether these people today accept or not, but just as the Promised Messiah(as) said one day they will have to accept that these are the Messianic arguments that the Promised Messiah(as) had presented and which demolished the Dajjal, and he indeed is the Promised Messiah(as).