My flesh will dwell secure

9 
Therefore my heart is glad, and my whole being rejoices;
    my flesh also dwells secure.
10 
For you will not abandon my soul to Sheol,
    or let your holy one see corruption [or the pit]
11 
You make known to me the path of life;
    in your presence there is fullness of joy;
    at your right hand are pleasures forevermore.
(Ps 16:9-11).

24 God raised him up, loosing the pangs of death, because it was not possible for him to be held by it. 25 For David says concerning him,“‘I saw the Lord always before me,    for he is at my right hand that I may not be shaken;26 therefore my heart was glad, and my tongue rejoiced;    my flesh also will dwell in hope.27 For you will not abandon my soul to Hades,    or let your Holy One see corruption.28 You have made known to me the paths of life;    you will make me full of gladness with your presence.’29 “Brothers, I may say to you with confidence about the patriarch David that he both died and was buried, and his tomb is with us to this day. 30 Being therefore a prophet, and knowing that God had sworn with an oath to him that he would set one of his descendants on his throne, 31 he foresaw and spoke about the resurrection of the Christ, that he was not abandoned to Hades, nor did his flesh see corruption (Acts 2:24-29).

Liberals think Peter is quoting Ps 16 out of context. They also think Peter's argument relies on the distinctive wording of the LXX. Some evangelicals agree, but think this is a case of sensus plenior. If so, that weakenes the appeal to prooftext the Resurrection. What are we to make of these objections?

i) Peter didn't necessarily, or even probably, quote the LXX. More likely, Luke substituted the LXX when he translated Peter's speech. We need to distinguish between Peter's audience and Luke's audience. 

ii) How we should render Ps 16:10b is disputed. "Corruption" is a defensible rendering. But based on Hebrew parallelism, where v10b is the counterpart to v10a, most scholars think it means "the pit." That creates a synonymous parallel between the grave and the pit.

"Sheol" could either be a prosaic word for the grave, or a metaphorical word for the grave which trades on Netherworld connotations.

iii) Whether Peter's argument turns on the rendering of the Hebrew word depends on what we think Peter is attempting to prooftext. Even if it means "the pit" rather than "corruption," that doesn't ipso facto invalidate Peter's argument.

iv) Liberals assume the original context has reference to deliverance from premature death rather than the afterlife. In other words, they assume it's about God sparing the Psalmist from dying, rather than God rescuing the Psalmist from Sheol after he dies. 

There is, however, nothing in the text itself that singles out that mundane interpretation. Rather, the liberal interpretation is based on the presupposition that at the time the Psalm was written, Israelites didn't believe in the afterlife. Their outlook was this-worldly. Liberals assume an evolutionary view of OT theology, where belief in the afterlife is a later development. 

However, belief in the afterlife was widespread in the ancient world. That antedates the OT. So it would be odd if Israel was the one ANE culture that didn't espouse the afterlife. Cf. E. Yamauchi, "Life, Death, and Afterlife in the Ancient Near East," R. Longenecker, ed. Life in the Face of Death: The Resurrection Message of the New Testament (Eerdmans 1998), 21-50. 

What's distinctive to ancient Israel wasn't belief in the afterlife, but belief in the general resurrection or resurrection of the just. In that regard, that's what set it apart from other ANE cultures.

v) Is Peter using Ps 16 to prooftext the Resurrection, the incorruptibility of Christ's body, or both? If he's only using Ps 16 to prooftext the Resurrection, then his argument doesn't depend on whether we render 16:10b be as "corruption" or "the pit."

vi) In addition, there's the question of what prevents his body from undergoing decay. In context, that would be the Resurrection. Absent the Resurrection, his body would be subject to decay. Of course, that's a gradual process. 

Not to "see corruption" doesn't necessarily (or even probably mean) no decay whatsoever, but rather, an inexorable process of decay–inasmuch as the only thing which would halt or reverse that process is the resurrection of the body. 

If Christ's body was incorruptible, it's unclear how that's an argument for the Resurrection. In fact, that's in tension with an argument for the Resurrection, for in that event, it doesn't require the Resurrection to preserve it intact. If it's incorruptible, it could remain in the tomb for millennia without undergoing dissolution. 

But that's hardly germane to Peter's argument. To the contrary, the point is not that God will preserve the body in the grave, as if the grave is the decedent's final resting place, but that God will restore the decedent to life–"in the flesh." 

vii) Liberals don't regard Ps 16 as a Davidic Psalm, much less a Messianic Psalm. In the evangelical interpretation, David prefigures Christ. In typology, the type is both analogous and disanalogous to the antitype. Peter highlights the contrast. A thousand years have passed since David wrote this hopeful psalm, yet David is still dead! His mortal remains are in the tomb. His body undoubtedly underwent progressive decay, until only bones are left. 

So this psalm refers first and foremost, not to David, but to Christ. Yet this will circle around. Because Christ rose from the dead, eventually David will rise from the dead. God will not ultimately abandon him to Sheol. It will be fulfilled in David because it was fulfilled in Jesus. 

In sum, we needn't appeal to a sensus plenior to salvage Peter's argument. He didn't rip the passage out of context.