Narragansett people
Arnold had a good relationship with the Narragansett people and, according to Elisha Stephen Arnold's family genealogy (1935), "he felt for the Indians a conscientious kindliness and in his dealings with them was actuated by a sense of strictest justice." Like Roger Williams, he also made an effort to learn their language and acted as interpreter many times; he was paid 26 shillings for his services in one instance. Being able to communicate with the Indians also enabled him to buy large tracts of land from them, and soon he and his sons owned nearly . In 1650, he paid taxes amounting to more than three and a half pounds, and his son Benedict paid five pounds—the highest taxes paid in the colony, implying that the Arnold family was among the wealthiest families in the colony in terms of land holdings.