Background 

On the death of Pandit Lekh Ram, Hazrat Mirza Ghulam Ahmad (as) warned those who opposed him that they were in reality at war with God. He invited them to test his claim and believe in him. Maulavi ‘Abdul Haq Ghaznavi wrote a highly abusive poster against Hazrat Mirza Ghulam Ahmad (as) in which he raised silly objections and challenged the knowledge of Arabic of Hazrat Mirza Ghulam Ahmad (as) and invited to hold a contest in Arabic with him so that the question could be established who knew Arabic better.

Hazrat Mirza Ghulam Ahmad (as) immediately accepted the offer of a contest and said that since he had no knowledge of Arabic and that he was an illiterate according to Maulavi ‘Abdul Haq Ghaznavi, if as a result of the contest he was overwhelmed in the debate, which would be nothing short of a miracle of God, then the Maulavi would have to offer his hand in bai‘at and join the Ahmadiyyah Jama‘at. Maulavi ‘Abdul Haq Ghaznavi and his friend, Shaikh Najfi, a Shia, remained silent and refused to honour his own invitation to hold a contest. 

The Book 

Hazrat Mirza Ghulam Ahmad (as) offered them a fresh sign. He wrote this book in Arabic which he began on March 17, 1897 and completed on May 26, 1897, and asked his opponents, particularly Maulavi ‘Abdul Haq Ghaznavi and Shaikh Najafi, (both had written abusive letters to Hazrat Mirza Ghulam Ahmad (as) and made assertions that he did not know Arabic) and Maulavi Muhammad Hussain Batalavi, to produce a book at least comparable to his Arabic and produce the like of it in the same manner within three or four months, then they can treat me as a liar. Further, they were welcome to enlist aid from anyone in producing a book of similar size, using prose and poem and invite Professor Maulavi ‘Abdullah or anyone scholar who can swear that their written book was superior or even equal to mine in quality and the scholar swearing in such manner will be seized by divine punishment within 41 days. If he survives I will burn all my books and will seek repentance on their hands, this will settle daily bickering between me and them and if they do not advance to accept the challenge then their falsehood would be exposed to the public. He allowed them to appoint a professor of Arabic to act as a judge and let him make his award under solemn oath. Hazrat Mirza Ghulam Ahmad (as) said if the adjudicator declared that the work of his opponents was superior to his, he would pray to God and if the judge was not then overtaken by the wrath of God within a period of 41 days, he would burn all his books and stand condemned. But no one had the courage to accept this daring challenge.

In this book, which bore the title of Hujjatullah, Hazrat Mirza Ghulam Ahmad (as) spoke of the various signs which God had shown in his favour. He also pointed out the error of his Shia opponents. In a graphic and eloquent manner, he explained that the Shia beliefs were not right, because the Caliphs, Hazrat Abu Bakr (ra), Hazrat ‘Umar (ra) and Hazrat ‘Uthman (ra), were the rightful Caliphs and Hadrat ‘Ali (ra) had acknowledged them so.

(Taken from the book an introduction to the hidden treasures of Islam, pp. 193-195.)