In Alma
10:22-23, we read of the efficacy of petitionary prayer:
Yea, and I say unto you that if it were not for the prayers of the righteous, who are now in the
land, that ye would even now be visited
with utter destruction; yet it would not be by flood, as were the people in
the days of Noah, but it would be by famine, and by pestilence, and the sword. But it is by the
prayers of the righteous that ye are spared; now therefore, if ye will cast
out the righteous from among you then will not the Lord stay his hand; but in
his fierce anger he will come out against you; then ye shall be smitten by
famine, and by pestilence, and by the sword; and the time is soon at hand
except ye repent.
Such shows
that prayer is indeed powerful and can be used to result in God relenting his wish
to demonstrate his (righteous) wrath against sinful people. For more on this,
see the section “The Bible is both God-centered and Man-centered” in my paper An
Examination and Critique of the Theological Presuppositions Underlying Reformed
Theology