The offering of sacrifice, in addition to being symbolic of the atonement, was an act meant to show gratitude to the Lord (see Lev 7:11-12). After leaving Jerusalem, Lehi offered sacrifice in thanksgiving, he built an altar of stones, and made an offering unto the Lord, and gave thanks unto the Lord our God (1 Nephi 2:7). Benjamin's people follow the same pattern in offering thanks for their blessings. Notice the wisdom of what they are thankful for. They are not thankful that they are a chosen and a holy people, as the Zoramites prayed (Alma 31:18). They are thankful for deliverance from Jerusalem, for deliverance from the Lamanites, for good teachers, and a righteous king. They exhibited appropriate gratitude to the Lord, for in nothing doth man offend God, or against none is his wrath kindled, save those who confess not his hand in all things (DC 59:21).
Joseph F. Smith
"I believe that one of the greatest sins of which the inhabitants of the earth are guilty today is the sin of ingratitude….We see a man raised up with extraordinary gifts, or with great intelligence, and he is instrumental in developing some great principle. He and the world ascribe his great genius and wisdom to himself. He attributes his success to his own energies, labor and mental capacity. He does not acknowledge the hand of God in anything connected with his success, but ignores him altogether and takes the honor to himself." (Gospel Doctrine, p. 270 as taken from Latter-day Commentary on the Book of Mormon compiled by K. Douglas Bassett, p. 204)