“On 1 April 1743, after a brief period serving a church on Long Island, Brainerd began working as a missionary to Native Americans, which he would continue until late 1746 when worsening illness prevented him from working. In his final years, he also suffered from a form of depression that was sometimes immobilizing and which, on at least twenty-two occasions, led him to wish for death. He was also affected by difficulties faced by other missionaries of the period, such as loneliness and lack of food. His first missionary task was working at Kaunameek, a Housatonic Indian settlement near present day Nassau, New York, twenty or thirty miles from missionary John Sergeant who was working in Stockbridge, Massachusetts. Brainerd remained there for one year. During this period he started a school for Native American children and began a translation of the Psalms. Subsequently, he was reassigned to work among the Delaware Indians along the Delaware River northeast of Bethlehem, Pennsylvania, where he remained for another year, during which he was ordained by the Newwark Presbytery. After this, he moved to Crossweeksung in New Jersey, where he had his most fruitful ministry. Within a year, the Indian church at Crossweeksung had 130 members, who moved in 1746 to Cranbury where they established a Christian community. In these years, he refused several offers of leaving the mission field to become a church minister, including one from the church at East Hampton on Long Island. He remained determined, however, to continue the work among Native Americans despite the difficulties, writing in his diary:
‘[I] could have no freedom in the thought of any other circumstances or business in life: All my desire was the conversion of the heathen, and all my hope was in God: God does not suffer me to please or comfort myself with hopes of seeing friends, returning to my dear acquaintance, and enjoying worldly comforts’.
David Brainerd traveled over 3000 miles, on horseback, as a missionary to the Indians.”