It could be argued grammatically that the adverbial phrase "according to the will of God" modifies the participle "commit" rather than the verb "suffer". There is really no way to prove either notion grammatically. If that were the case, it could be translated as Rotherham proposes, "So then, let, them who are even suffering, according to the will of God ... be committing their souls, in well–doing." This would be a restatement of 2:15, where Paul writes, "for so is the will of God, that with well-doing you put to silence ignorant men". These verses are purporting that God's will is our commitment to well doing, not necessarily our suffering. By implication, this also reinforces the overall idea of 3:17, where Paul writes, "for it is better, if the will of God be so, that you suffer for well-doing rather than for evil doing." The two key phrases in all three aforementioned passages are, 1) "will of God", and 2) "well-doing". Therefore, we must not advocate that it is God's will that we suffer. For Peter himself, in the same context, reiterates God's faithfulness to protect us from physical danger and grant us "good days" (see Peter's reference to Psalm 34:12-16 in 1 Pet 3:10-13 -- Psalm 34 is clearly a promise of physical protection and longevity). Surely Peter's reference to Psalm 34 demonstrates his trust in its present application, including its several assertions concerning protection (Psa 34:7, 17, 19). In addition, even if Peter is advocating that God allows persecution, surely Peter is emphasizing verbal persecution (1 Pet 2:12, 3:16, cf. Mt 5:11), not necessarily physical harm. So we can still stand on promises for physical protection and longevity, which are numerously presented in scripture (e.g. Psa 34, Psa 91, Psa 46, Prov 1:31, Prov 3:1-2, etc.).
In Summary:
1) If we are suffering, it better be for "well doing", rather than evil doing (1 Pet 2:20, 3:17, 4:15-16)
2) God does not will our suffering, but the "well doing" which inevitably results in persecution
3) This "well doing" puts to shame our persecutors (3:16), and wins many of them over to the Gospel (2:12)
4) The suffering Peter is referring to is primarily verbal persecution (2:12, 3:16)
5) God will deliver us from physical harm (3:10-13, cf. Psa 34)
6) This deliverance should not presumed to be automatic, but secured conditionally through faith and obedience (Mk 11:22-24, James 1:6-7, etc.)