>>712671
>why missing church is a mortal sin and not venial
Missing Mass is grave matter, because the Church has witnessed and declared it as such. Since she is the pillar and foundation of truth, we are obliged to obey. Not out of obligation, but out of love for our fellow human beings.
>>712685
Hell is not the punishment for sin. The choice of sin is a choice away from God. If I sin and do not repent, I am stating I do not love God more than the sin. I wish to be excluded from God and the blessed.
CCC 1033 This state of definitive self-exclusion from communion with God and the blessed is called "hell."
God is love, and love does not force itself upon others. That would be rape. If a human being cannot love God because they cling to a sin, God will give that person what they desire.
>>712685
>Do you have to know and fully understand how something is a mortal sin for it to be “full consent”?
You must have knowledge that it is grave matter. Now that you read this here, you may not believe, but you know. The question of fully understanding DOES play a part. If I have a mental disablement that prevents me from processing what I have been taught, I don't have full understanding. Good point to review as I didn't cover this.
>>712685
>Does this teaching deny or work in detriment to the gratuity of grace?
Gratitude is an act of love. If I love God with my whole heart and mind, and I live in a repentant life moment by moment, I will naturally express gratitude for the work of God's mercy through His Son, Jesus.
>wouldn't be living in a full state of grace
Exactly correct. It is not required for us to be in a full state of grace but to be in A state of grace.
St. Joan of Arc - "If I am in grace, may God keep me there. If I am not in grace, my God bring me there."