From the book Pioneer Pathways DUP vol.1 p. 376

The Porters, together with the Morris Phelps and Baldwin Clark families, bought some very rich farmland near what is now Peoria. Sanford saw the need for a sawmill inasmuch as the population was growing and people were building homes. With the help of Morris Phelps, he built a mill. Before it was in operation, Sanford bought his partner out, and he and his boys ran it. They found it took all of their time, so they sold the farm and moved into the mill.
One morning two men came to the Porter home. They handed Sanford a letter from Morris Phelps, who had moved near Chicago. The letter introduced the two gentlemen as missionaries from a church Sanford had never heard of. Sanford had always been spiritual and had studied the Bible diligently but had never belonged to a church. Morris said the missionaries had been preaching in the vicinity and that ministers from all the area churches were in an uproar over their message. He wanted Sanford, because he knew the Bible so well, to hear them out and then write him about Sanford’s thoughts on their message. Sanford and Nancy listened and prayed about it and were baptized August 10, 1831, as well as their children, Chauncey, Malinda, and Sarah. Sanford was set apart as a missionary and labored with Nathan Sumner in the nearby towns. About sixty miles away he found his old partners, Morris Phelps, Baldwin Clark, and John Cooper who listened to the missionaries and joined the Church of Jesus Christ of Latter- day Saints. Shortly thereafter, two missionaries came to Tazewell County on their way to Kirtland, Ohio. They informed the new members that the authorities of the Church wished all to gather in Jackson County, Missouri. Nancy and Sanford put the mill up for sale. Sanford instructed all the families that he had been called to preside over, to prepare to go to the “New Zion” in Missouri.