Christian’s dating all the way back to the very first generation who learned the faith from the Apostles themselves have petitioned Saints in Heaven to pray for them to God. We find evidence of this practice in the Roman Catacombs dating all the way back to the first century but where in scripture do we find evidence that the Saints in Heaven have the ability to hear our prayers?
In Revelations 6:10 John paints a pretty clear picture that the Saints in Heaven are aware of what is happening down on Earth. He tells us about the Martyr’s in Heaven are aware that there murderers are still alive and there death’s have not yet been avenged by God.
they cried out with a loud voice, “O Sovereign Lord, holy and true, how long before thou wilt judge and avenge our blood on those who dwell upon the earth?”
Later on in Revelation 8:4 John goes on to show that these Saints pray (Revelation 5:8) and do so before God himself in Heaven.
and the smoke of the incense rose with the prayers of the saints from the hand of the angel before God.
We also see in Tobit 12:12 that the Angel Raphael is aware of prayers that happen on Earth and even specifically says he brought these petitions to God himself.
And so, when you and your daughter-in-law Sarah prayed, I brought a reminder of your prayer before the Holy One; and when you buried the dead, I was likewise present with you.
We also know that in 1 Timothy Chapter 2 Saint Paul commands us to pray for one another, a practice that the Saints in Heaven also practice. Since they have no need to pray for themselves it stands to reason they would pray for us. As shown above, we have clear evidence from the Old and New Testament that they are aware of whats going on Earth and pray on our behalf.