This short excerpt is from a letter Martin Luther wrote to his father as he neared death. The words of comfort it gives are still valid today.
“We have yonder a true mediator with God, Jesus Christ, who has overcome death and sin for us and now sits in heaven with all his angels, looking down on us and awaiting us so that when we set out we need to have no fear or care lest we should sink and fall to the ground. He has such great power over sin and death that they cannot harm us, and he is so heartily true and kind that he cannot and will not forsake us, at least if we ask his help without doubting. Jesus has overcome the world and we need not have a care.”
He also added these words. quoting from the Catechism: “Our departure from this life is a smaller thing to God than my journey would be to Mansfeld or yours from Mansfeld to Wittenberg. It is only an hour’s sleep, and after that all will be different. This is most certainly true.”

For more Martin Luther quotes see:
Martin Luther on the Kingdom of God