I always thought Purgatory and praying for the dead made perfect sense.
The Bible gives us its description of sin which the Catholic Church uses to support its teaching that there is a division in sins. Even a young child knows the consequences and severity of murdering someone is quite different from taking a cookie from the cookie jar when you were told to wait until after supper. Thus the Church teaches that there is mortal sin and venial sin.
Unless you are heartily sorry and cry out, beg, plea for God's mercy and forgiveness for having offended thee, and I detest all my sins because of thy just punishment, I firmly resolve with the help of thy grace (which Catholics are blessed to receive in the sacramental seal of confession) to sin no more and to avoid the near occasion of sin Amen you will go to hell for one.
Not for the other lesser sin of gobbling your Momma's fresh baked cookies that were staring you in the face. Or, as my past history case, snatching my mother's little frozen condensed-milk-with-nuts-dipped-in-chocolate-balls during the weeks leading up to the Christmas Eve party.
Thank God I knew my mother and God loved me enough not to send me to hell for that trifle truffle. ;-)
Quite honestly I'm relieved that I God loves my unconditionally and I am not such an awful person so I probably won't go straight to Hell so I needn't live my life in a state of fear but, rather, in a state of hope and faith. God even loves the murderer so our hope in His mercy and love is endless.
But let's be realistic. God is most holy, most pure. I'm also relieved I won't go before the Lord God Almighty until I have been thoroughly cleansed...sinful creature that I am...because I am by no means as perfect as He. As the young child must be disciplined and corrected for snatching those cookies (or delicious little milky chocolate balls that melt in your mouth!), so should we be disciplined...with mercy. God is a loving god. He is also a just god.
The Ten Commandments and the Golden Rule should serve as our Guide to Heaven. To know God is to love Him. To love God is to desire to serve Him.