These verses in 3 Nephi teach about avoiding the giving of money to the poor openly or praying and fasting openly to be seen of others. The Lord encourages us to practice righteousness in private. President Thomas S. Monson explained the value of anonymous service:
“I approached the reception desk of a large hospital to learn the room number of a patient I had come to visit. This hospital, like almost every other in the land, was undergoing a massive expansion. Behind the desk where the receptionist sat was a magnificent plaque which bore an inscription of thanks to donors who had made possible the expansion. The name of each donor who had contributed $100,000 appeared in a flowing script, etched on an individual brass placard suspended from the main plaque by a glittering chain.
“The names of the benefactors were well known. Captains of commerce, giants of industry, professors of learning—all were there. I felt gratitude for their charitable benevolence. Then my eyes rested on a brass placard which was different—it contained no name. One word, and one word only, was inscribed: ‘Anonymous.’ I smiled and wondered who the unnamed contributor could have been. Surely he or she experienced a quiet joy unknown to any other. …
“A year ago last winter [1981], a modern jetliner faltered after takeoff and plunged into the icy Potomac River. Acts of bravery and feats of heroism were in evidence that day, the most dramatic of which was one witnessed by the pilot of a rescue helicopter. The rescue rope was lowered to a struggling survivor. Rather than grasping the lifeline to safety, the man tied the line to another, who was then lifted to safety. The rope was lowered again, and yet another was saved. Five were rescued from the icy waters. Among them was not found the anonymous hero. Unknown by name, ‘he left the vivid air signed with his honor’ (Stephen Spender, ‘I think continually of those—’ in Masterpieces of Religious Verse, ed. James Dalton Morrison [New York: Harper and Brothers Publishers], p. 291.) …
“May this truth [service] guide our lives. May we look upward as we press forward in the service of our God and our fellowmen. And may we incline an ear toward Galilee, that we might hear perhaps an echo of the Savior’s teachings: ‘Do not your alms before men, to be seen of them’ (Matthew 6:1). ‘Let not thy left hand know what thy right hand doeth’ (Matthew 6:3). And of our good deeds: ‘See thou tell no man’ (Matthew 8:4). Our hearts will then be lighter, our lives brighter, and our souls richer.
“Loving service anonymously given may be unknown to man—but the gift and the giver are known to God” (in Conference Report, Apr. 1983, 73–74, 76; or Ensign, May 1983, 55–57).