The scene filled Isaiah with a profound sense of unworthiness, and he cried out, "Woe is me! for I am undone; because I am a man of unclean lips, and I dwell in the midst of a people of unclean lips: for mine eyes have seen the King, the Lord of hosts" (v. 5). Wishing he could join in the praises sung by the angels, but realizing his unworthiness to do so, it was the uncleanness of his lips he lamented. And then a strange thing happened. One of the angels broke from his worshipful reverie and flew to Isaiah, "having a live coal in his hand, which he had taken with the tongs from off the altar: And he laid it upon my mouth, and said, Lo, this hath touched thy lips; and thine iniquity is taken away, and thy sin purged" (v. 6-7). His sins remitted, his iniquity cleansed, Isaiah's lips were opened, and he could, like the angels, converse with the Divine.
This experience stuck with Nephi, who quoted Isaiah at length, both in his public discourse and in his religious writings. He spoke boldly about the need to follow the Savior's example of baptism, linking the angel's act to this ordinance by proclaiming that after baptism "cometh a remission of your sins by fire" (2 Nephi 31:17). And then, like Isaiah, "can ye speak with the tongue of angels, and shout praises unto the Holy One of Israel" (2 Nephi 31:13).
I think that the reason for this is twofold--first, baptism cleanses us so that we are worthy to join in the angels' praise. But secondly, and perhaps more importantly, the effects of baptism elicit praise from us--that is, the cleansing effect of the Atonement that becomes active in our lives because of our obedience, repentance, humility, and faith sweeps away our guilt and fills us with joy, peace, and love, which causes us to praise the goodness of God. Amulek declared, "now is the time and the day of your salvation; and therefore, if ye will repent and harden not your hearts, immediately shall the great plan of redemption be brought about unto you" (Alma 34:31). Mormon counseled, "baptism cometh by faith unto the fulfilling the commandments; and the fulfilling the commandments bringeth remission of sins; And the remission of sins bringeth meekness, and lowliness of heart; and because of meekness and lowliness of heart cometh the visitation of the Holy Ghost, which Comforter filleth with hope and perfect love, which love endureth by diligence unto prayer" (Moroni 8:25-26).
With baptism for the remission of sins, and the accompanying refining presence of the Holy Ghost, we become both worthy and eager to join the "numberless concourses of angels" that Lehi saw, "in the attitude of singing and praising their God" (1 Nephi 1:8). Alma, beholding the same scene, remarked, "my soul did long to be there" (Alma 36:22). Rising from his coma, Alma praised the Lord, proclaiming that he had "been born of God" (v. 23).
Moroni's closing words invite us, having been cleansed, to join in the praise of God's power, "Yea, come unto Christ, and be perfected in him, and deny yourselves of all ungodliness; and if ye shall deny yourselves of all ungodliness, and love God with all your might, mind and strength, then is his grace sufficient for you, that by his grace ye may be perfect in Christ; and if by the grace of God ye are perfect in Christ, ye can in nowise deny the power of God" (Moroni 10:32).
I have experienced a portion of God's limitless power, transcendent grace, and infinite love, and I, like the prophets before me, cannot deny the power of God. I know that the same God who created the universe and its inhabitants, who daily grants them life and breath, has redeemed all mankind who will return and repent and exercise faith in the Lord Jesus Christ, who came "not...to condemn the world, but that the world through him might be saved" (John 3:17). The cleansing He offers and the holiness He imparts through His infinite Atonement are the greatest gifts in creation. In the times I have known that priceless joy, that sweet release, I, too, have felt to shout praises to the Holy One of Israel.
Holy, holy, holy, is the Lord God Almighty. Truly, the whole earth is full of his glory.