The only significant difference from Matthew 6:1–4 is found in verse 1. The phrase “Verily, verily, I say that I would that ye should do alms unto the poor,” is added. It is interesting to speculate why this addition was appropriate in the New World. Aiding the poor has been a Nephite teaching from the beginning, but the descriptions of Nephite society in the years leading up to the sign of Christ’s birth, and then the time leading up to the signs of his death, suggest that the Nephite nation had begun to turn its back on assisting the poor. When the Book of Mormon describes the Nephites being increased in pride during their times of riches, one of the complaints is that they neglect the poor. It is perhaps a reminder of this duty that was important at this point.
The sayings on alms are not given only to reinforce the need for them, but to discuss our personal relationship to them. This section of the Sermon on the Mount begins a series of examples which will end with the conclusion that those who do seemingly righteous things for the glory that might come to them from men will have their reward. That is, if they do things so that men will regard them, then it is only men who will so regard them, not God.
The underlying message of all of these is that what God requires is not simply our actions, but that the motivations for our actions be correct.