“The Lord your God is a jealous God”
When a second child is born into a family the first one may give evidence of jealousy. When the little one sees Mommy or Daddy holding a new brother or sister, jealousy stirs in their heart. The first child does not want any “rivals” for their parent’s affection.
Even the family dog can become jealous of an infant “intruder” who receives some of the affection and attention that was formerly theirs alone.
Jealousy is occasionally a destructive force in the family system. The older brother or sister may revert to sucking their thumb—or other activities that they left behind—as they began to grow older. They crave all of their parent’s attention and are upset when they feel threatened by the new arrival. They may misbehave and have temper tantrums to regain the lost attention.