Timothy was in need of encouragement. Paul reminded him of the faith that he had received from his mother and grandmother. Timothy had become fearful of some situation and needed to rekindle the gift that God had given him when Paul laid hands on him. Timothy had become intimidated and Paul called upon him to remember.
Paul wanted Timothy to remember the Spirit that God had given him. Instead of being intimidated and fearful, God had given him a Spirit of power, love, and self-control.