I heard a sermon touching on this by a non-Catholic preacher that has been hard to ignore.
Hebrews 11:1 states that “Faith is the realization of what is hoped for and evidence of things not seen.” In Matt 21:22, Jesus says “Whatever you ask for in prayer with faith, you will receive,” and again in Mark 11:24, “Therefore I tell you, all that you ask for in prayer, believe that you will receive it and it shall be yours.”
This guy’s point was that if you believe you will receive it, you will not need to pray a second time unless your faith was not strong enough the first time.
As far as the reading from last week’s Gospel about the persistent widow, I always hear how that scripture means we should “nag” God. (Yes, a theologian in our diocese writing in the Catholic Advance weekly newspaper actually used the word “nag.”) What I haven’t heard addressed from the pulpit, and it was addressed by that other preacher, was the last verse, Luke 18:8,“I tell you, he will see to it that justice is done for them speedily. But when the Son of Man comes, will he find faith on earth?”
Why is this last question asked? Doesn’t it imply that God will answer those whose cry out to him day and night, while at the same time saying their nagging resulted from their lack of faith? Does this not correlate with Jesus’ calming the storm, in which he calmed the storm because they cried out to them, but then told them they had little faith for doing so?
In direct response to your question, if I feel stronger in faith than when I prayed for something the first time, I might pray for it again. Otherwise I try to avoid repetitions of petition prayer.
Alan