“If so, why not ask the saints, too?”
Because although they are alive in Christ, they are dead, and the Bible says so, and we are expressly forbidden to contact the dead.
I was just reading the account of Saul praying to the dead Samuel last night as a matter of fact. Sin.
So they are alive. And we don't "contact the dead" we ask for their prayers; not to get nosy news.
As far as being forbidden to contact the dead, see Leviticus 19:31:
“Do not turn to mediums or necromancers; do not seek them out, and so make yourselves unclean by them: I am the LORD your God."
This is what Saul was doing.
1 Samuel 28 deals with Saul contacting a witch, who he asked to summon up the spirit of the prophet Samuel (whether this really *was* Samuel, or, witches being witches, a deceiving spirit masquerading as Samuel, I don't know). Saul asked Samuel to give him advice (v. 15):
"And Samuel said to Saul, Why hast thou disquieted me, to bring me up? And Saul answered, I am sore distressed; for the Philistines make war against me, and God is departed from me, and answereth me no more, neither by prophets, nor by dreams: therefore I have called thee, that thou mayest make known unto me what I shall do."
So Saul was consorting with a witch for the purposes of asking someone for advice: which is not the same as asking a fellow believer (who has gone on to Heaven, presumably) , to pray *to GOD* on your behalf.
Cheers!