That's called intercession. And that is what is happening here. (Someone asks me to pray for you and I ask God that you be healed.) Really simple.
The first miracle worked by Christ at Cana was done through the intercession of Mary, the Mother of Christ. Simple, no?
So from that, you extrapolate a policy of calling on the dead, to get God's attention... The Mormon's have seized on an obscure text which allows them to baptize themselves for a dead person's benefit. does that seem like the same thing, to you?
Where is this tradition found in the Scriptures?
IMO, we only need speak to God!
6 But when you pray, go into your room and shut the door and pray to your Father who is in secret; and your Father who sees in secret will reward you. 7 "And in praying do not heap up empty phrases as the Gentiles do; for they think that they will be heard for their many words. 8 Do not be like them,for your Father knows what you need before you ask him. 9 Pray then like this: Our Father who art in heaven, Hallowed be thy name. 10 Thy kingdom come. Thy will be done, On earth as it is in heaven. 11 Give us this day our daily bread; 12 And forgive us our debts, As we also have forgiven our debtors...
1 Therefore, my brethren dearly beloved and longed for, my joy and crown, so stand fast in the Lord, my dearly beloved. 2 I beseech Euodias, and beseech Syntyche, that they be of the same mind in the Lord. 3 And I intreat thee also, true yokefellow, help those women which laboured with me in the gospel, with Clement also, and with other my fellowlabourers, whose names are in the book of life. 4 Rejoice in the Lord alway: and again I say, Rejoice. 5 Let your moderation be known unto all men. The Lord is at hand. 6 Be careful for nothing; but in every thing by prayer and supplication with thanksgiving let your requests be made known unto God. 7 And the peace of God, which passeth all understanding, shall keep your hearts and minds through Christ Jesus. 8 Finally, brethren, whatsoever things are true, whatsoever things are honest, whatsoever things are just, whatsoever things are pure, whatsoever things are lovely, whatsoever things are of good report; if there be any virtue, and if there be any praise, think on these things. 9 Those things, which ye have both learned, and received, and heard, and seen in me, do: and the God of peace shall be with you.
Jesus, God Incarnate, spoke of getting God's attention, not some saint, or even his mom. She was a vessel, used by God, just as the clay pot! Paul, another vessel of God's choice, was a Jewish scholar, blinded and changed... Peter was a fisherman, to whom God revealed the mysteries of life, on a roof top, and gave freedom a visual reference. He was not the head of the church, he was called a rock... and denied Christ! He was another vessel... but no more impotant than the pot of water, turned to wine! They all served to point at God in our midst!