In late May 1933, Sr Faustina was transferred to Vilnius to work as the gardener, here tasks including growing vegetables. She remained in Vilnius for about three years until March 1936. The convent in Vilnius then had only 18 sisters and was housed in a few scattered small houses, rather than a large building.
Shortly after arriving in Vilnius, Sr Faustina met the priest Michael Sopoćko, the newly appointed confessor to the nuns. He was also a professor of pastoral theology at Stefan Batory University, now called Vilnius University.
When Sr Faustina went for the first time to this priest for confession, she told him that she had been conversing with Jesus, who had a plan for her. After some time, Sopoćko insisted on a complete psychiatric evaluation of Sr Faustina by Helena Maciejewska, a psychiatrist and a physician associated with the convent. This took place in 1933 and Sr Faustina passed the required tests and was declared of sound mind.
Sopoćko then began to have confidence in Sr Faustina and supported her efforts. He also counseled her to begin keeping a diary and to record the conversations and messages from Jesus of which she had told him. Kowalska told Sopoćko about the Divine Mercy image, and in January 1934, Sopoćko introduced her to the artist Eugene Kazimierowski, who was also a professor at the university.
By June 1934, Kazimierowski had finished painting the image, based on the direction of Sr Faustina and Sopoćko, the only Divine Mercy painting that Sr Faustina saw. A superimposition of the face of Jesus in the Image of the Divine Mercy upon that in the already-famous Shroud of Turin shows great similarity.
Sr Faustina wrote in her diary (Notebook I, Item 414) that on Good Friday, 19 April 1935, Jesus told her that he wanted the Divine Mercy image to be publicly honoured.A week later, on 26 April 1935, Sopoćko delivered the first sermon ever on the Divine Mercy, and Sr Faustina attended the sermon.
The first Mass during which the Divine Mercy image was displayed occurred on 28 April 1935, the second Sunday of Easter, and was attended by Sr Faustina. It was also the celebration of the end of the Jubilee of the Redemption by Pope Pius XI. Sopoćko obtained Archbishop Romuald Jałbrzykowski's permission to place the Divine Mercy image within the Gate of Dawn Church, in Vilnius, during the Mass that Sunday, and he celebrated the Mass himself.
On 13 September 1935, while still in Vilnius, Sr Faustina wrote of a vision about the Chaplet of Divine Mercy in her diary (Notebook I, Item 476). The chaplet is about a third of the length of the Rosary. Sr Faustina wrote that the purpose for the chaplet's prayers for mercy is threefold: to obtain mercy, to trust in Christ's mercy, and to show mercy to others.
In November 1935, she wrote the rules for a new contemplative religious congregation devoted to the Divine Mercy. In December, she visited a house in Vilnius that she said she had seen in a vision as the first convent for the congregation.
In January 1936, Sr Faustina went to see Jałbrzykowski to discuss a new congregation for Divine Mercy. However, he reminded her that she was perpetually vowed to her current order. In March 1936, she told her superiors that she was thinking of leaving the order to start a new one that was specifically devoted to Divine Mercy, but she was transferred to Walendów, southwest of Warsaw. She reported that Jesus had said to her: "My Daughter, do whatever is within your power to spread devotion to My Divine Mercy, I will make up for what you lack."