Excellent post, Seeker. I am glad that you pointed out 1John 5:15-16. But obviously Ayodhya already knew about it but chose not to acknowledge it. I say this because he quoted a part of #1854 of the Catechism, as follows:
"Sins are rightly evaluated according to their gravity." Pg. 454, #1854
But then he left out the line that came right after that: "The distinction between mortal and venial sin,
already evident in Scripture, became part of the tradition of the Church." The CCC clearly footnoted that statement with 1John 5:16-17. Ayodhya has done this sort of thing in the past. He will quote the CCC but ignore any footnoted Scripture passages that are used to defend Catholic positions. As you may recall, he did this exact same thing in the topic on "Celibacy" and I pointed it out.
Now, to Ayodhya, here are the answers to some of your questions:
What specifically constitutes a mortal sin?
See CCC# 1857-1861 (it's spelled out in detail).
How much repentance does it take to get one forgiven?
As a general rule, repentence offered with a firm purpose of amendment is what is required. This can be done in a single act of repentence.
How do I know when one is forgiven?
In terms of the Sacrament of Reconciliation, if a Catholic makes a good confession (backed with a firm purpose of amendment) and is granted absolution, he is forgiven when he fulfills the act of penance his confessor gives him.
Why is the Bible silent on the subject?
What subject? Mortal and venial sin"? But, as Seeker pointed out, the bible is
not silent on that. And, as I pointed out, you knew it.
Tragically, the Catechism does not provide answers to any of these questions.
Every answer I just gave is in the Catechism.
While God does expect His children to confess their sins to Him, once sins are confessed and forgiven, God makes a wonderful promise:
"And their sins and iniquities will I remember no more." Hebrews 10:17
And exactly where do Catholics say otherwise?
Catholicism, though, demotes the Lord and robs Him of the honor and glory that He alone deserves, by declaring that lowly sinners can help pay for varying degrees of sins through their good works.
A person does not "pay" for sins, but he must participate in this salvation by living a life of faith. That includes good works.
Melody wrote about this at length two weeks ago in the discussion on sacraments. It was a very good post and she backed it up with Scripture, and yet you have not responded to it.
But apparently, you still deny the importance of good works. Therefore I challenge you to give me an interpretation of the following passage:
"Above all hold unfailing your love for one another, since love covers a mulitude of sins. Practice hospitality ungrudgingly to one another." (1Pet 4:8-9) If good works don't mean anything in terms of salvation, then how does my love and hospitality for another "cover a mulitude of sins"?
And for that matter, why did the "goats" go to hell in the Parable of the Sheep and the Goats? (Mt 25:31-42)
The only reason that Matthew states is because the goats did not engage in acts of charity.And for that matter, explain to me why the the bible says:
"Be doers of the word, and not hearers only, deceiving yourselves" (James 1:22), and
"Religion that is pure and undefiled before God and the Father is this: to visit orphans and widows in their affliction, and to keep oneself unstained from the world" (James 1:27), and
"You see that a man is justified by works and not by faith alone." (James 2:24), and
"Faith without works is dead" (James 2:26), and
"For He will render to every man according to his works...For it is not the hearers of the law who are righteous before God, but the doers of the law who will be justified." (Romans 2:6,13)God bless,
-Rev. Eric