Jesus spent a good deal of the next part of his sermon teaching about the nature of our Father in heaven by discussing private daily devotions. Do not, he said, make a public show of doing that which is better done in private—almsgiving, welfare relief, fasting, and personal prayer—for “thy Father who seeth in secret, himself shall reward thee openly.”
A central message of several teachings in 3 Nephi 13 is to be careful not to do good things just to be seen of men. Satan always sponsors his own imitation of righteous principles; for example, we should seek glory but not the glory of men. Our immediate and ultimate objective is to have our eye single to the glory of God. We should “do [our] alms,” all our righteous acts, secretly and quietly.
Latter-day Saints are some of the most generous people in the world; they give a high percentage of their time, labor, and resources to do the work of God and bless the lives of others. It is part of the gospel of Jesus Christ to share, but we should do so without fanfare and without seeking public recognition.