What is the Unforgivable Sin?

Blasphemy is the only unforgivable sin.

Definition of Blasphemy:  (Merriam-Webster)
     1. the act of insulting or showing contempt or lack of reverence for God.
     2. irreverence toward something considered sacred or inviolable.

       
However, the scripture below tells us that blasphemy against God or Jesus Christ can still be forgiven, it's only blasphemy against the Holy Spirit. 

Matthew 12:31-32  "And so I tell you, every kind of sin and slander can be forgiven, but blasphemy against the Spirit will not be forgiven. Anyone who speaks a word against the Son of Man (Jesus) will be forgiven, but anyone who speaks against the Holy Spirit will not be forgiven, either in this age or in the age to come."

If You Commit Suicide, Do You Go to Hell?

The Bible can be very confusing at times and many people get frustrated trying to understand this topic. All we can do look at examples of scripture.

Both Samson and King Saul committed suicide, but we believe both of them will be in heaven.

1 Samuel 31:4-5 "...But his armor-bearer was terrified and would not do it; so Saul took his own sword and fell on it. When the armor-bearer saw that Saul was dead, he too fell on his sword and died with him."

We expect to see Saul in heaven from the following verse:

1 Samuel 10:10  "...the Spirit of God came powerfully upon him, and he joined in their prophesying."

The fact is, ALL sins are serious enough to send us to HELL. God commanded us not to murder, but His only son, Jesus Christ, died for our sins (past, present, and future sins) so that we can inherit eternal life in Heaven.  Committing suicide is essentially murdering yourself, which is a sin just like lying, stealing, fornicating, etc.  All of which, Christ's death paid for.