(A) "In the Bible it talks about if you give your life to God...then basically your slate is wiped clean."
1st John 1:9 "If we confess our sins He (God) is faithful and just to forgive us our sins and cleanse us from all unrighteousness."
This is God's promise to all of us. Whether we are coming to God for the first time or fifty years later. God forgives our sins...and cleanses us..that means the blood of Jesus Christ washes away our sin. Jesus has paid the penalty for it. This was God's plan. When He sent Jesus to live among us; He showed us what God is truly like. He didn't just live some perfect holy man's life. It was a loving, forgiving and compassionate life. He was loving, forgiving and compassionate to the people around Him..especially those who had great and desparate needs.
We all need God's forgiveness..some realize it more than others.
(B) "In my church, my pastor preaches this ALL the time, but when someone asks to become a member of the church...you would think that no matter what that person did in the past their slate is clean. "
When Jesus came to earth..it was not to be a judge of mankind. He came as a help...a savior.
But after His work on earth was finished and the Father raised Him up to heaven again; God gave Jesus the name which is above all names. Now, whenever a man or woman dies, we must each face the Lord Jesus Christ and give an accounting. Some will face Jesus as a terrible Judge..those who did not call on His sacrifice, His death on the cross..and ask for the free gift of His forgiveness..then they will face His wrath for scorning the price He paid for their sins.
The rest of us..those who cried out for His blessing and forgiveness..we'll still give an accounting of what we did..but ours will be for rewards and heaven...not judgement and hell.
(C) "Not the case...so, I wonder if my pastor preaches what the Bible says and does the opposite does that make him a hypocrite? "
There is a Proverb that says,
"The mind of a man plans his way,
but the Lord directs his steps."
I think we try
to do our best;
our best intentions.
Why not talk to your Pastor in private...ask him.