Ecclesiastes 9:5-6 states, "For the living know that they will die, but the dead know nothing they have no further reward and even their name is forgotten. Their love, their hate and their jealousy have long since vanished never again will they have a part in anything that happens under the sun."
I'll use the typical Orthodox cop-out here. Because that passage was in the Old Testament, none of the dead were actually in Paradise, merely with Abraham in a place of rest. When Christ descended to raise up those in Hades, they were, as Anastasios said, deified in Christ.
One of my favorite writings is St. John Chrysostom Paschal Homily, which explains that act very well:
"He that was taken by death has annihilated it! He descended into hades and took hades captive! He embittered it when it tasted his flesh! And anticipating this Isaiah exclaimed, "Hades was embittered when it encountered thee in the lower regions." It was embittered, for it was abolished! It was embittered, for it was mocked! It was embittered, for it was purged! It was embittered, for it was despoiled! It was embittered, for it was bound in chains!...Christ is risen, and not one dead remains in a tomb!"
In addition, because Orthodox and Catholics do not follow the idea of Sola Scriptura
(that is, truth is found ONLY through the Scripture), our teachings come from the Holy Tradition of the Church, of which Scripture is merely a subset. For example, the Bible does not explicitly state that the Trinity exists, but that is the Tradition (big 'T') that the Church has passed down through the ages, affirmed through the Ecumenical Councils, and is therefore correct.
To give a brief answer, nowhere in the Bible does it state, without a doubt, that praying to the saints means they will pray for you. Only minor hints, like Fr. Chris pointed out. That does not make us doubt its truth, however.
Hope that clarifies things without muddying the waters even more. And I am sorry if this sounded condescending, as I'm not sure how far you are on your path of Orthodoxy or how much you have learned about it thus far.