Eusplagchnos literally means 'of good bowels' — in Greek physiology, the bowels (splagchna) were the seat of deep emotion, just as in English we speak of 'gut feelings.' The word describes someone with a tender, compassionate inner life — genuinely moved by the suffering of others. The related verb splagchnizomai ('to be moved with compassion') is used repeatedly of Jesus in the Gospels.
The two NT uses of eusplagchnos (Ephesians 4:32, 1 Peter 3:8) embed compassion in the core of Christian ethics. Ephesians 4:32: 'Be kind and compassionate [eusplagchnos] to one another, forgiving each other, just as in Christ God forgave you.' The logic is: God forgave you; therefore, have tender hearts toward others. 1 Peter 3:8 lists it among virtues for harmonious community life. The tenderness of God toward sinners — expressed ultimately in the cross — is the model for the church's tenderness toward one another.