There is a thief prowling about your life attempting to steal the gift of life that God has designed for you. That thief is named "unforgiveness."  The Lord's Prayer comes to God asking that He forgive us just as we have been forgiven. It's not that God's forgiveness isn't available but many times we do not experience the freedom it brings because we are still holding onto the unforgiveness of others.
We selfishly hold onto our justifications and reasoning for not forgiving but in the eyes of God there is no room for justification.  He has promised us that if we confess our sins He is faithful and righteous to forgive us our sins and to cleanse us from all unrighteousness. God cannot lie but we may never experience the freedom that comes from His forgiveness when we are allowing our hearts to hold onto unforgiveness. 
Much of the discord and barriers we experience in our relationships is due to us holding onto our unforgiveness. We experience physical and emotional issues due to the bitterness that builds a stronghold in our lives due to unforgiveness. 
Could it be that we have never really known the forgiveness that God has offered to us through Jesus Christ. Could it be our lack of understanding of the price that was paid in order that we could have the forgiveness of God is keeping us from being able to offer true forgiveness? 
This Christmas season give the best gift of all; forgiveness!