Grieve a nature that brings pain and at times, depression or revolt and opposition. We in our life would have grieved many people, either by our thought, words or behavior. We never look back on how they would have felt or how they would response. The base behind all these is our SELF. We are more important than the one who we respond. One and only one reason we grieve other, is to prove we were correct and build a nature of no forgiveness or understanding others. The moment we try to give importance to others and their views, and more specifically put ourselves in their shoe we will understand the impact that Grieve will produce.
Do not grieve the Holy Spirit of God, by whom you were sealed for the day of redemption