The Nature of Bitterness

Ephesians 4:26 And “don’t sin by letting anger control you.” Don’t let the sun go down while you are still angry, 27 for anger gives a foothold to the devil.
31 Get rid of all bitterness, rage, anger, harsh words, and slander, as well as all types of evil behavior. 32 Instead, be kind to each other, tenderhearted, forgiving one another, just as God through Christ has forgiven you.

2nd Samuel 3:22 But just after David had sent Abner away in safety, Joab and some of David’s troops returned from a raid, bringing much plunder with them. 23 When Joab arrived, he was told that Abner had just been there visiting the king and had been sent away in safety. 24 Joab rushed to the king and demanded, “What have you done? What do you mean by letting Abner get away? 25 You know perfectly well that he came to spy on you and find out everything you’re doing!” 26 Joab then left David and sent messengers to catch up with Abner, asking him to return. They found him at the well of Sirah and brought him back, though David knew nothing about it. 27 When Abner arrived back at Hebron, Joab took him aside at the gateway as if to speak with him privately. But then he stabbed Abner in the stomach and killed him in revenge for killing his brother Asahel. 28 When David heard about it, he declared, “I vow by the Lord that I and my kingdom are forever innocent of this crime against Abner son of Ner. 29 Joab and his family are the guilty ones. May the family of Joab be cursed in every generation with a man who has open sores or leprosy or who walks on crutches or dies by the sword or begs for food!” 30 So Joab and his brother Abishai killed Abner because Abner had killed their brother Asahel at the battle of Gibeon.

Matthew 18:1 About that time the disciples came to Jesus and asked, “Who is greatest in the Kingdom of Heaven?” 2 Jesus called a little child to him and put the child among them. 3 Then he said, “I tell you the truth, unless you turn from your sins and become like little children, you will never get into the Kingdom of Heaven. 4 So anyone who becomes as humble as this little child is the greatest in the Kingdom of Heaven.
5 “And anyone who welcomes a little child like this on my behalf is welcoming me. 6 But if you cause one of these little ones who trusts in me to fall into sin, it would be better for you to have a large millstone tied around your neck and be drowned in the depths of the sea.

Job 42:7 After the Lord had finished speaking to Job, he said to Eliphaz the Temanite: “I am angry with you and your two friends, for you have not spoken accurately about me, as my servant Job has. 8 So take seven bulls and seven rams and go to my servant Job and offer a burnt offering for yourselves. My servant Job will pray for you, and I will accept his prayer on your behalf. I will not treat you as you deserve, for you have not spoken accurately about me, as my servant Job has.” 9 So Eliphaz the Temanite, Bildad the Shuhite, and Zophar the Naamathite did as the Lord commanded them, and the Lord accepted Job’s prayer. 10 When Job prayed for his friends, the Lord restored his fortunes. In fact, the Lord gave him twice as much as before!