After having been expelled by the inhabitants of Ammonihah, Alma was "wading through much tribulation and anguish of soul," when an angel of the Lord appeared to him and declared that he had been sent to "command [Alma] that thou return to the city of Ammonihah, and preach again unto the people of the city" (8:16).
Before he issued the command, however, the angel cheered Alma by telling him that he was "blessed," and by encouraging him to "lift up his head and rejoice," in spite of his deep and painful soul-searching. He mentioned not only that Alma had been faithful since the time of his conversion, but that he, the angel, was the same angel who had appeared to deliver the Lord’s message the first time. These words and reassurances must have meant a great deal to Alma. President Henry B. Eyring has pointed out how well Alma had taught his son, Corianton, "who was mired in the misery of sin. Alma knew that wickedness could never be happiness for his son—or for any child of Heavenly Father. He taught his son that increasing in holiness was the only path to happiness." Because Alma learned this truth the hard way, and was able to speak authoritatively about it to his children.
President Henry B. Eyring, "Holiness and the Plan of Happiness," October 2019 General Conference.