Hazrat Jalal-ud-Din Shams (ra) in his introduction to this book says:

“The Promised Messiah (as) wrote this book on May 15, 1908, in eleven days before his demise. This book also includes an essay on pages 373-436 that the Promised Messiah (as) wrote and which was read at the religious conference held by Aryah Samaj Movement in December 1907 in Lahore. Wherein the Promised Messiah (as) made a fervent plea to Aryah Samaj Movement for stopping vile attacks on Holy Prophet (sa), but nonetheless they continued attacks, so in this book, he drew a comparison between the teachings of Vedas and the Holy Quran and enumerated the signs of a living religion. The other part of the book stated that Guru Baba Nanak was a Muslim divine and adduced proofs in support of his contention from the holy book of the Sikh religion."

The Book 

Hazrat Mirza Ghulam Ahmad (as) started writing the lecture on November 8, 1907, and completed a 69-page long dissertation on the subject by December 2, 1907, Hazrat Maulavi Hakim Nuruddin (ra) was selected to read the speech as Hazrat Maulvi Abdul Karim (ra) had died by that time. As agreed, Hazrat Mirza Ghulam Ahmad (as) also sent a delegation of Ahmadis to take part in the conference. His article was read on December 3, 1907, and despite the pleadings of Maulavis that people should not go to listen to this address, there was a heavy rush.

In this speech, Hazrat Mirza Ghulam Ahmad (as) first discussed the nature of the revelation and the beliefs of various faiths on revelations. He particularly mentioned the group of the people who assert that God does not speak and no revelation could now take place. In this connection, he explained the beauties of Islam and its worldwide appeal and the advent of prophets taking place in various nations at various times and then mentioned in detail the great advent of the Holy Prophet (sa) and the teachings he brought and the majesty of revelation in Islam. He asserted with all the emphasis at his command that Islam is the only religion that can show the real face of God and introduce the real and living revelation.

The next day, contrary to all promises and commitments of all the people, the Secretary of the Aryah Samaj delivered a filthy lecture in which he heaped vile abuses and obscene attacks on the personage of the Holy Prophet (sa) and what was more offensive, that the lecture was delivered by the man who held out repeated assurances of good behaviour and decency. When the report reached Hazrat Mirza Ghulam Ahmad (as) about this treacherous attack, he was extremely angry and enquired as to why the members of the Ahmadiyya delegation continued sitting at the meeting when such a vile and virulent attack was being launched on the noble personage of the Holy Prophet (sa). Everybody, including Hazrat Maulavi Hakim Nuruddin (ra), heard this broadside and upbraiding, then eventually one of the participants, Maulavi Muhammad Ahsan, fell on knees and submitted that they had made a mistake and he should pardon them for this lapse however serious it was. It may be mentioned here that Hazrat Mirza Bashiruddin Mahmud Ahmad (ra), son of Hazrat Mirza Ghulam Ahmad (as), who was only 17 years old (later became the Second Caliph), made repeated protestations at the meeting to leave such a gathering.

Hazrat Mirza Ghulam Ahmad (as) could not bear the idea of letting the attacks of the Aryah Samaj go unchallenged, so he wrote a fitting reply to their unwarranted attacks. To answer the attacks of the Aryah Samaj, Hazrat Mirza Ghulam Ahmad (as) drew a comparison between the teachings of the Holy Quran and the teachings of the Vedas. He specially mentioned the qualities of a revealed book and enumerated the characteristics of a living religion and thereby established the superiority of Islam. Hazrat Mirza Ghulam Ahmad (as) gave resounding arguments on the blessings and graces conferred by the Holy Prophet (sa) on humanity, and recounted the signs of Islam as a living religion. This part of the article became the first part of the book, Chashma-e-Ma‘rifat, and the speech delivered at the meeting became the second part of the book.

The lecture also included arguments that Baba Guru Nanak was a true Muslim and quoted the teachings of Granth Sahib, which were more or less based on the Holy Quran. This book remains, to this day, a milestone in rebuttal of the Aryah Dharam and the Vedas. This book is also an outstanding testimony to the deep love, devotion and respect that the Promised Messiah (as) had entertained for his mentor and master, the Holy Prophet (sa). The passages of the book were replete with signs of attachment that he had with Holy Prophet Muhammad (sa).

(Taken from An Introduction to the hidden Treasures of Islam)