Don't you think God will answer Himself as He promised He would?
Do you not trust Him to hold to His word and do as He promised?
I trust God's promises, but I'm not interpreting his promises the way you are. If the above argument were a decisive argument against praying to saints or Mary, it would also be an argument against ever asking another human being to pray for us; yet we see Paul request prayers all the time from the recipients of his letters. Likewise James says, "Is anyone among you sick? Let them call the elders of the church to pray over them and anoint them with oil in the name of the Lord. And the prayer offered in faith will make the sick person well; the Lord will raise them up. If they have sinned, they will be forgiven. Therefore confess your sins to each other and pray for each other so that you may be healed. The prayer of a righteous man is powerful and effective." James links prayer efficacy to the righteousness of the one praying, and to the authority of church leaders in the case of the elders praying over the sick. The saints are more righteous and more authoritative than me, so I welcome their prayers. I also welcome when God answers my prayers that are directed directly to Him, which He often does. But He doesn't promise He's always going to answer every prayer "yes" instantly regardless of conditions. Sometimes God wants us to persist in prayer for prolonged periods ("This kind can come out by nothing but prayer and fasting"--Matthew 17:21), and sometimes He denies our requests. We see Jesus praying all night in Luke 6:12 before choosing his Apostles, which He wouldn't need to do if prayer always required merely making a simple short request. And we see the Father denying Jesus' prayer to take the cup from Him in Luke 22:42. Was God contradicting 1 John 5:15 by denying Jesus' prayer request there? I think not.
That's one of the weakest 'Catholic' arguments on this subject, of them all.
It is one thing to ask for prayers of the living, it is yet another things to make requests to those who have passed on to await final judgement.
If you desire to include Paul in this as some kind of recommendation, show us where Paul advised such requests be made of those who had passed on (who had died earthy, physical death), or else be honest, and leave Paul out of it entirely...