Mosiah 16:9-15

9  He is the light and the life of the world; yea, a light that is endless, that can never be darkened; yea, and also a life which is endless, that there can be no more death.
10  Even this mortal shall put on immortality, and this corruption shall put on incorruption, and shall be brought to stand before the bar of God, to be judged of him according to their works whether they be good or whether they be evil—
11  If they be good, to the resurrection of endless life and happiness; and if they be evil, to the resurrection of endless damnation, being delivered up to the devil, who hath subjected them, which is damnation—
12  Having gone according to their own carnal wills and desires; having never called upon the Lord while the arms of mercy were extended towards them; for the arms of mercy were extended towards them, and they would not; they being warned of their iniquities and yet they would not depart from them; and they were commanded to repent and yet they would not repent.

Mosiah 16:9-12 (Emphasis mine)

Abinadi ends his praise of Christ in verse 9.  He praises Christ, calling him the endless light, which can never be darkened, and there will be no more death.

1  THE LORD is my light and my salvation; whom shall I fear?  the LORD is the strength of my life; of whom shall I be afraid?

Psalms 27:1 (Emphasis mine)

4  In him was life; and the life was the light of men.
5  And the light shineth in darkness; and the darkness comprehended it not.

John 1:4-5 (Emphasis mine)

12  ¶ Then spake Jesus again unto them, saying, I am the light of the world: he that followeth me shall not walk in darkness, but shall have the light of life.

John 8:12 (Emphasis mine)

14  Wherefore he saith, Awake thou that sleepest, and arise from the dead, and Christ shall give thee light.

Ephesians 5:14 (Emphasis mine)

Then he reminds them that the day will come when they will stand before God and be judged according to their works.  The righteous will receive eternal life and happiness; the wicked to endless damnation, being subject to the devil..

Abinadi tells them that those who receive damnation  receive it because of the choices they made (a very common thread throughout the Book of Mormon).  In spite of the fact that the Lord reached out to them, warned them of their sins, and commanded them to repent, they ignored all the efforts of the Lord on their behalf.  They chose to continue in their wicked ways, and thereby earned the judgment of damnation they will receive.

Remember, the wicked, in Abinadi's words, "...never called upon the Lord while the arms of mercy were extended towards them..." (v12)  What more can we ask of the Lord than He extend his arms of mercy to us?  He is showing us His deep and abiding love for us.  He reaches out to us.  He is doing everything He can to bring us back to Him.  And, the response of the wicked is to "...never [call] upon the Lord..." (v12)  What would it be like to stand before Him someday, and know that He did everything He could to redeem you and forgive you of your sins, but ignored it.  You blew it!  And you're going to have to live through the eternities with this knowledge.  This has to be the true meaning of Hell.

David R. Seely pointed out that the phrase "...the arms of mercy..." (v12) is unique to the Book of Mormon.  He writes:

"In the Book of Mormon, the phrase 'his arm of mercy is extended' also signals the Lord's power on behalf of the penitent and the believer (Jacob 6:5; Mosiah 29:20; Alma 19:36)..

"The arm of mercy. The first is the image of the arm of mercy extended. The phrase 'arm of mercy' is not in the Old Testament. The closest phrase that suggests such an image is in Psalm 94:18: 'When I said, My foot slippeth; thy mercy, O Lord, held me up.' Mercy can also be extended (see, for example, Psalm 109:12), but it seems to be used in the same sense as show mercy.

"The phrase occurs eight times in the Book of Mormon. It appears first when Jacob explains Zenos' allegory of the olive tree: 'While his arm of mercy is extended towards you in the light of the day, harden not your hearts' (Jacob 6:5). If read in context, this phrase is a continuation of the hand imagery that Jacob had introduced three verses earlier: 'The day that he shall set his hand again the second time to recover his people, is the day, yea, even the last time, that the servants of the Lord shall go forth in his power, to nourish and prune his vineyard' (6:2).

"The image of the arm of mercy also occurs in Mosiah 16:12; Alma 5:33; 19:36; 29:10; and 3 Nephi 9:14. Each time, the Lord is offering 'to all people who will repent and believe on his name' (Alma 19:36) the chance to take full advantage of the Atonement. For example, 'Behold, he sendeth an invitation unto all men, for the arms of mercy are extended towards them, and he saith: Repent, and I will receive you" (Alma 5:33).' "

The Image of the Hand of God in the Book of Mormon and the Old Testament, David R. Seely, Maxwell Institute, (Emphasis mine)

42  So also is incorruption:

1 Corinthians 15:42 (Emphasis mine)

2  And many of them that sleep in the dust of the earth shall awake, some to everlasting life, and some to shame and everlasting contempt.

Daniel 12:2 (Emphasis mine)

13  And now, ought ye not to tremble and repent of your sins, and remember that only in and through Christ ye can be saved?
14  Therefore, if ye teach the law of Moses, also teach that it is a shadow of those things which are to come—
15  Teach them that redemption cometh through Christ the Lord, who is the very Eternal Father.  Amen.

Mosiah 16:13-15 (Emphasis mine)

Abinadi is finishing his teachings.  He reminds them that only through Christ can they be saved.  After all he has said, he tells them they should "...tremble and repent of [their] sins..." (v13). 

He reminds them that, by teaching the Law of Moses, they are teaching that ultimately redemption and salvation will come through Christ.  The Law of Moses is simply a shadow of things to come.

"In their conception of history, Book of Mormon prophets consider types as significant, instructive, and persuasive in focusing on Christ's earthly advent, his visit to the Nephites, and his second coming and heavenly kingdom ... Abinadi before King Noah's court insists, 'If ye teach the law of Moses, also teach that it is a shadow of those things which are to come' (Mosiah 16:14)"

"That Jesus Is the Christ" - Typology, Richard Dilworth Rust, Maxwell Institute, accessed July 12, 2011.  (Emphasis mine)

"God the Father is the author of the gospel; it is a key part of God’s plan of salvation, or plan of redemption. It is called the gospel of Jesus Christ because it is the Atonement of Jesus Christ that makes redemption and salvation possible. Through the Atonement all men, women, and children are unconditionally redeemed from physical death, and all will be redeemed from their own sins on the condition of accepting and obeying the gospel of Jesus Christ..." (Emphasis mine)

Have We Not Reason to Rejoice? President Dieter F. Uchtdorf, October 2007 General Conference

"The gospel is the good news of Christ. It is the revelation that the Son of God came to earth, lived a perfect life, atoned for our sins, and conquered death. It is the path of salvation, the way of hope and joy, and the assurance that God has a plan of redemption and happiness for His children."

The Way of the Disciple, President Dieter F. Uchtdorf, April 2009 General Conference (Emphasis mine)  

15  But God will redeem my soul from the power of the grave: for he shall receive me.  Selah.

Psalms 49:15 (Emphasis mine)

8  And an highway shall be there, and a way, and it shall be called The way of holiness; the unclean shall not pass over it; but it shall be for those: the wayfaring men, though fools, shall not err therein.
9  No lion shall be there, nor any ravenous beast shall go up thereon, it shall not be found there; but the redeemed shall walk there:

Isaiah 35:8-9 (Emphasis mine)

14  I will ransom them from the power of the grave; I will redeem them from death: O death, I will be thy plagues; O grave, I will be thy destruction: repentance shall be hid from mine eyes.

Hosea 13:14 (Emphasis mine)

29  ¶ The next day John seeth Jesus coming unto him, and saith, Behold the Lamb of God, which taketh away the sin of the world.

John 1:29 (Emphasis mine)

Once Abinadi finishes his words, he stands before king and priests, awaiting his fate.