Have you noticed Hebrews 12:1? And therefore we also having so great a cloud of witnesses over our head, laying aside every weight and sin which surrounds us, let us run by patience to the fight proposed to us:
Now I have never seen the "witnesses" (Fans) of any race that just sat stoically by, have you? How much more so would the saints in heaven intercede for us in our own races knowing of the eternal consequences of it?
Now if the New Testament says that we are surrounded by a great cloud of witnesses as we run our race for the Lord, just what do we think those folks are doing? Ever been to a race? No one sits there stoically, do they?
To me this passage makes it pretty clear that the faithful departed are not only aware of what we do (This of course by the will and power of God!), but they are actively interceding for us the way that race fans do.
I find it even harder to grasp how any soul that has won through so far as heaven or purgatory (knowing the struggles and spiritual warfare that all the "church militant" endures) would not be busily interceding for those of us running our race that has such eternal consequences. That just doesn't sound like any of the faithful believers that I have ever heard of.
These witnesses can see the race.
How much more would the saints in heaven intercede (Oh look! Evidence for the intercession of Saints!) for those of us still running our races, especially since that race has such eternal consequences?
Here's a link to a great Bible study on the Communion of Saints. Here's the basic notes.
Well worth it.
As to the charge of necromancy:
It's not necromancy, you need to understand the Communion of Saints.
If our dead brothers and sisters are not aware of us then why does Hebrews 12:1 say that we are surrounded by a great cloud of witnesses in our race for the Kingdom of God?
Romans 8:38: For I am sure that neither death, nor life, nor angels, nor principalities, nor things present, nor things to come, nor powers,
39: nor height, nor depth, nor anything else in all creation, will be able to separate us from the love of God in Christ Jesus our Lord.
To non-Catholics who might disagree:
So you never ask anyone else to pray for you?
When you "got saved", did anyone else pray along with and for you? By your thinking that was wrong since all you needed was to pray for yourself.
Yet what does the Word of God say? I desire therefore, first of all, that supplications, prayers, intercessions, and thanksgivings be made for all men: (1st Timothy 2:1)
The saints pray in Heaven:
Revelation 5:8 And when he had opened the book, the four living creatures, and the four and twenty ancients fell down before the Lamb, having every one of them harps, and golden vials full of odours, which are the prayers of saints:
Revelation 8:3 And another angel came, and stood before the altar, having a golden censer; and there was given to him much incense, that he should offer of the prayers of all saints upon the golden altar, which is before the throne of God. 4 And the smoke of the incense of the prayers of the saints ascended up before God from the hand of the angel.