The question revolves around the social reform movement of 19th century which was initiated by people like Raja Ram Mohun Roy, Ishwar Chand Vidya Sagar etc. The key words in the question are purify and rediscover. Therefore you have to base your answer on the fact that these reformers were not trying to force reforms in Indian society from European point of view but wanted to overhaul the society through rationale and informed discussion of Indian religious textbooks.
In the intro, mention the work of these reformist leaders and what were the evils present in the Indian society at that time (sati practice, prohibition on widow remarriage, infanticide etc.)
The main body should focus on how early social reformers wanted to enlight Indians that Sati, infanticide etc should be banned not because that would be conformant with the European ideals of rationalism, empiricism, monotheism and individualism but because they are not allowed in the Indian religious text. How they wanted to preserve the society while changing the behaviors of its members.
(This was the sole reason why they translated the original text into Vernacular. They knew that Indians are too religious and they can only accept these reforms when they can prove them that these practices had no basis in religious text.)
Nineteenth century is the period of turmoil in Indian society. The age-old traditions and practices were degraded and these were replaced by many social evils like female infanticide, sati, child-marriage, caste system, purdah; ban on female education, and widow re-marriage etc. The conquest of India by the British during the 18th and 19th century exposed some serious weaknesses and drawbacks of Indian social institutions. The most distressing was the position of women. The socio intellectual revolution that took place in the fields of social reforms is often known as Indian Renaissance. An important part of European Renaissance was reforming society from outside, on the basis of Post Enlightenment rationalism. But in Indian context, it implied rediscovering rationalism from within India’s past.
It was done through following ways:
The most important result of the impact of western culture was the replacement of blind faith in current traditions, beliefs, and conventions by a spirit of rationalism.
Reformists adopted a rational approach to tradition but also evaluated the existing socio-religious practices from the position of social utility and to replace faith with rationality.
In the Brahmo Samaj, it led to the repudiation of the infallibility of the Vedas, and in the Aligarh Movement, to the reconciliation of the teachings of Islam with the needs of the modern age.
Syed Ahmed Khan emphasized that if religion did not keep pace with and meet the demands of the time it would get fossilized as in the case of Islam in India.
The socio religious reform movement was against backward element of traditional culture in terms of both religious and social evils.
The focus was on regeneration of traditional institutions including medicine, education, and philosophy and so on.
There were differences in methods of those reform movements but all of them were concerned with the regeneration of society through social and educational reforms.
The social reform movement did not, however, attack the social system as a whole; their attack was mainly only on the perversions and distortions that had crept into it.
They did not advocate a sharp rupture in the existing social structure of the country.
They did not stand for structural transformation; changes were sought within the framework of the very structure.
The religious texts were translated into vernacular languages.
There was more emphasis on interpretation of scriptures and simplification of rituals, thus making worship a more personal experience.
The reformers aimed at modernisation rather than outright westernization.
The main means used for the propagation of ideas add for the creation of favourable public opinion were the urban communication channels such as the press, lectures, and sabhas, propaganda network.
A favourable social climate was created to end India’s cultural and intellectual isolation from the world.
In India, social reforms did not ordinarily mean a reorganisation of the structuring of society at large, as it did in the West, for the benefit of underprivileged social and economic classes. Instead, it meant the infusion into the existing social structure of the new ways of life and thought. The idea was – “The society would be preserved, while its members would be transformed.” The social reform movement, as a matter of fact, was not an isolated phenomenon; it was loaded with wider national political and economic considerations. In a way, the social reform movement was a prelude to nationalism.