CCC 2094 lists the following as mortal sins:
"One can sin against God’s love in various ways:
- indifference neglects or refuses to reflect on divine charity; it fails to consider its prevenient goodness and denies its power.
- ingratitude fails or refuses to acknowledge divine charity and to return him love for love.
- lukewarmness is hesitation or negligence in responding to divine love; it can imply refusal to give oneself over to the prompting of charity.
- acedia or spiritual sloth goes so far as to refuse the joy that comes from God and to be repelled by divine goodness.
- hatred of God comes from pride. It is contrary to love of God, whose goodness it denies, and whom it presumes to curse as the one who forbids sins and inflicts punishments."
The last one is quite clear, but I’m not entirely sure what the others are talking about. What constitutes “refusing to acknowledge divine charity,” or “refusal to give oneself over to the prompting of charity,” for example? I would really appreciate some knowledgeable insight.