By 1825 many slaves had come to see Christianity as the religion of slave-owners, and, with the door to the Christian church virtually closed to them, growing numbers turned to Islam. In 1825, the first year in which records were kept, there were 846 male and 422 female Muslims. Some observers believed that, by the mid-1830s, most Cape Town slaves were Muslims. The authorities were becoming concerned about the rapid spread of Islam.
Slave-owners slowly began to devote themselves with greater energy to win slaves for Christianity. They had come to believe that Christianity could help rather than hinder the owners in controlling their slaves. Landdrost Stockenstrom and the Graaff-Reinet heemraden wrote in a 1826 letter: ‘[The] more they [the slaves] made religious principles their own, the better they would be as servants and the greater the benefits to their owners.’ But the Dutch Reformed Church (DRC) left this field largely to the Zuid-Afrikaansche Zending Genootschap and other missionary societies, and to the English churches. Until Emancipation Day the rate of slave baptism and confirmation in the DRC remained very low.