You are absolutely correct in saying that faith in the Lord Jesus Christ will save you.  We read in John 3:36, “He that believeth on the Son HATH EVERLASTING LIFE: and he that believeth not the Son shall not see life; but the wrath of God abideth on him.”  We read in Romans 10:9, “That if thou shalt confess with thy mouth the Lord Jesus, and shalt believe in thine heart that God hath raised him from the dead, THOU SHALT BE SAVED.”  The Lord Jesus said in John 5:24, “Verily, verily, I say unto you, He that heareth my word, and believeth on him that sent me, hath everlasting life, and SHALL NOT COME INTO CONDEMNATION; but is passed from death unto life.”  Yes, it is clear in the scriptures that when one put his/her faith in the Lord Jesus Christ, they have eternal life and “SHALL NEVER PERISH.” (John 10:28).

What happens if you continue to sin even after you are saved?  First of all, believers still sin, even after we are saved.  John wrote to believers in 1 John 1:8 saying, “If we say that we have no sin, we deceive ourselves, and the truth is not in us.”  Notice the word ‘sin’ is in the singular.  This refers to the corruption of the old man still present in us, and the stain created by the actual sins coming from that old nature in us.  We still have that old nature, and it will cause us to commit sins.  As Christians, what do we do when we commit sins?  The very next verse instructs us, “If we confess our sins, he is faithful and just to forgive us our sins, and to cleanse us from all unrighteousness.”  When we sin, the Holy Spirit in us will convict us of that sin and with repentant hearts, we should confess this sin to the Lord.  When we repent and confess our sins (as believers), we will find that the Lord is both faithful and righteous.  He will forgive us, and He will cleanse us from ALL unrighteousness.  So, in our daily lives, we should confess our sins the Lord each time we commit a sin, so that we might continue to enjoy the fellowship and leadership of the Lord.

Now, let us consider 1 John 3:9, “No one who has been born of God practices sin, because His seed remains in him; and he cannot sin continually, because he has been born of God.” (NASB).  One who is truly born again will not continue in sin as before they were saved.  It is a sure sign of the presence of the Spirit in our lives that when we sin, we feel convicted of that sin and will desire the Lord’s forgiveness and restoration.

Your question seems to indicate that you have accepted the Lord Jesus as your savior and are concerned about the sin in your life.  This SOUNDS like one who knows the Lord and is concerned about continuing sin.  As we read at the outset, one who puts their faith in the Lord Jesus Christ as their savior is SAVED FOREVER and will NEVER PERISH, or go to Hell.  However, if you are allowing sin to rule in your life, you need to be before the Lord about this, confess this to Him, ask Him to give you the strength to overcome the temptation to sin.

Where does the strength to overcome sin come from?  It comes from a close relationship with the Lord.  Let me ask you…are you reading God’s Word daily?  Are you praying daily?  Are you fellowshipping often with fellow believers of ‘like faith’?  With a true heart to please the Lord, these are the things that will help you overcome sin and walk in fellowship with the Lord.  We read in Galatians 5:16, “This I say then, Walk in the Spirit, and ye shall not fulfil the lust of the flesh.”  When we are walking (or living) according to the leading of the Spirit, we will not give in to the lust of the flesh.  Sin will have a much less hold of us and will not appeal to us when we are seeking to live for the Lord according to His Word.  (CC)  (492.4)