- First of all, The ayah you're quoting is talking to the prophet when he was alive, to pray for them. You can ask anyone alive to pray for you if you think he's more pious than you (same thing as asking someone to help you change a tire). Second to ask someone for help is "Dua" which is a type of worship exclusive to Allah, (Example Ya Ali, Ya Hussein) Proof? read this:
"He causes the night to enter the day, and He causes the day to enter the night and has subjected the sun and the moon - each running [its course] for a specified term. That is Allah , your Lord; to Him belongs sovereignty.
And those whom you invoke other than Him do not possess [as much as] the membrane of a date seed."
If you invoke them, they do not hear your supplication; and if they heard, they would not respond to you. And on the Day of Resurrection they will deny your association. And none can inform you like [one] Acquainted [with all matters].
You answered by saying, and I quote:
"O Allah, I beseech Thee, and turn towards Thee,
through Thy Prophet,.."
Read this:
"We worship them only that they may
bring us closer to Allah."
5 Allah will surely judge between them concerning all that in which they differ.
6 Allah does not show guidance to any liar and denier of the truth.
7
"And they
worship other than Allah that which neither harms them nor benefits them, and they say, "These are our
intercessors with Allah " Say, "Do you inform Allah of something He does not know in the heavens or on the earth?"
Exalted is He and high above what they associate with Him"
That's a blatant lie, Shiites pray for Abbas and ask favors of him, Shiites throw papers filled with favors into graveyards all the time.