Bitterness can cause separation from God and separation from others.
When we feel anger and bitterness towards God or others, it can increase the risk of heart attack; increase the risk of some types of cancer; negatively impact cholesterol levels and sleep; and increase physical pain, blood pressure, levels of anxiety, depression and stress. We must learn to forgive. Our life and our health depend on it. 
Bitterness against God is sometimes caused when we don’t understand what God is doing, or why He has allowed something to occur that we didn’t want to have happen. But we must remember that God is holy (Isaiah 6:3) so He cannot sin and that He will right every wrong, either in this life or the next. (Psalm 103:6). Knowing how much He loves you can increase your trust in Him (1 John 4:16). Also, understand that we don’t always know what is happening in the spiritual realm. The crucifixion of Christ looked horrible in the physical realm, but it was a huge victory in the spiritual realm. Unless we have a complete understanding of all impacts in both realms, we cannot know if an event is horrible (like Christ’s death), or leading to something wonderful (like Christ’s resurrection and our redemption).
Bitterness towards others occurs when they have wronged us or someone we love in some way. But it is a serious sin because we are acting in God’s place as a judge on that person’s actions or motives. We are not the judge, God is (James 4:12). If bitterness is not dealt with it can progress into resentment, anger, hatred and violence.
For our body to function as God intends, we must get rid of bitterness towards God and others.
Day 6 Challenge: Today we will follow the steps below to stop the bitterness in our hearts.
Step 1: Admit the pain that has been caused.
Step 2: Pray and release the pain to God.
Step 3: Step out of the judge’s seat and let God be there.
Tomorrow we will look at unforgiveness and how that blocks our healing.
 Forgiveness, your health depends on it, John Hopkins Medicine. https://www.hopkinsmedicine.org/health/wellness-and-prevention/forgiveness-your-health-depends-on-it