19 And thus we see how merciful and just are all the dealings of the Lord, to the fulfilling of all his words unto the children of men; yea, we can behold that his words are verified, even at this time, which he spake unto Lehi, saying:
20 Blessed art thou and thy children; and they shall be blessed, inasmuch as they shall keep my commandments they shall prosper in the land. But remember, inasmuch as they will not keep my commandments they shall be cut off from the presence of the Lord.
21 And we see that these promises have been verified to the people of Nephi; for it has been their quarrelings and their contentions, yea, their murderings, and their plunderings, their idolatry, their whoredoms, and their abominations, which were among themselves, which brought upon them their wars and their destructions.
22 And those who were faithful in keeping the commandments of the Lord were delivered at all times, whilst thousands of their wicked brethren have been consigned to bondage, or to perish by the sword, or to dwindle in unbelief, and mingle with the Lamanites.
23 But behold there never was a happier time among the people of Nephi, since the days of Nephi, than in the days of Moroni, yea, even at this time, in the twenty and first year of the reign of the judges.

Therefore, O my son, whosoever will come may come and partake of the waters of life freely; and whosoever will not come the same is not compelled to come; but in the last day it shall be restored unto him according to his deeds (Alma 42:27).

Now, after contrasting the behavior of the Nephites with the behavior of their enemies–after pointing out the love, unity, and gratitude, the consistent religious observances, and the diligent preparations of the Nephites, Mormon wants to make sure that we see God’s mercy and justice at work in their lives. There was never a happier time among them, he tells us, than during this four-year period in which their decisions enabled them to receive the blessings and the protection of God. He reminds us that the wars and destruction which they experienced during much of their history (including during the time of Mormon) were a result of disobedience, which cut them off from the delivering power of God. The Nephites at this time experienced the mercy of God as a fulfillment of promises He had made to them. He always keeps His promises, which is a manifestation of His perfect justice.
Today, I will be grateful for God’s justice and mercy in my life. Because He is just, I know that He will fulfill His promises to me. Because He is merciful, I know that His saving power is available to me as long as I am willing to humble myself and keep His commandments. I will remember and be grateful that God’s dealings with us are both merciful and just.