Omni 1

Considering some of his forefathers, Amaleki seems to have bought into the teachings of Mosiah and the prophets as is final writings say -

"...I shall deliver up these plates unto him [king Benjamin], exhorting all men to come unto God, the Holy One of Israel, and believe in prophesying, and in revelations, and in the ministering of angels, and in the gift of speaking with tongues, and in the gift of interpreting languages, and in all things which are good; for there is nothing which is good save it comes from the Lord: and that which is evil cometh from the devil.
26 And now, my beloved brethren, I would that ye should come unto Christ, who is the Holy One of Israel, and partake of his salvation, and the power of his redemption. Yea, come unto him, and offer your whole souls as an offering unto him, and continue in fasting and praying, and endure to the end; and as the Lord liveth ye will be saved."  (Omni 1:25–26)