Baba Avtar Singh Ji succeeded Baba Buta Singh Ji and preached the divine message during the period from 1943 to 1962. He was all out for the uplift of mankind through dissemination of the divine word. He faced opposition from different fronts in carrying out his missionary obligations, but he remained moulded and welded to the Truth. He appeased the flood of opposition with his deep spirit of humility and love. He possessed wonderful skill to convince his critics, provided they chose to listen to him. There are many instances where critics, after listening to Baba Ji, joined the Mission and dedicated their lives to the propagation of its message.
Following the partition of India in 1947, Baba Avtar Singh Ji had to shift from Rawalpindi (now in Pakistan) to Paharganj, Delhi (India). Devotees migrating from Pakistan also maintained their contact with Baba Ji and sought rehabilitation in and around Delhi. In order to meet the requirements of the children of the devotees and others, Baba Avtar Singh Ji opened Sant Nirankari School in Paharganj, (which is now a Senior Secondary School). Subsequently, he also established Sant Nirankari Colony in North Delhi and shifted the Headquarters of the Mission there. Santokh Sarovar (now called Nirankari Sarovar) was also developed near the Colony.
The ideology of the Mission was easy to understand and follow in practical day-to-day life. It attracted people from all castes and communities. The Mission prescribed no cumbersome rituals or costly ceremonies and liberated people from all kind of taboos. Then, it loved all and hated none. The masses that had just experienced the havoc that communalism and religious intolerance could play with the mankind, gone through the misery before Partition and suffered from the agony even thereafter. They had not only seen the disease of casteism in its full swing, but felt the sting also, welcomed the Mission where all of them were treated as equally respected and dignified members of one human society. They found here what they really needed—the Mission under the spiritual leadership of Baba Avtar Singh Ji, was providing spiritual balm to heal their worldly wounds, the inner strength to bear the sorrow and the morale boosting to continue their journey of life.
The orthodox elements continued to harass Baba Avtar Singh. One day, while a congregation was going on at the residence of Baba Avtar Singh Ji, some people came and started shouting slogans against him. When they continued for some time and did not disperse, some of the disciples asked for Baba Ji’s permission to go and teach them a lesson. Instead Baba Ji asked some disciples to go and offer them water. The demonstrators felt very happy. But when they came to know that the water was being offered on behalf of Baba Avtar Singh Ji, they felt ashamed at their mistake and realized how He possessed divine qualities of compassion, love for all and forgiveness.