In his book, REFORMED SPIRITUALITY, Howard L. Rice begins his introduction of the book with the question taken from The Heidelberg Catechism, "What is your only comfort in life and in death?" He takes the next paragraph to quote this profound answer.
"That I belong--body and soul, in life and in death--not to myself but to my faithful Savior, Jesus Christ, who at the cost of his own blood has fully paid for all my sins and has completely freed me from the dominion of the devil; that he protects me so well that without the will of my Father in heaven not a hair can fall from my head; indeed, that everything must fit his purpose for my salvation. Therefore, by his Holy Spirit, he also assures me of eternal life, and makes me wholeheartedly willing and ready from now on to live for him."
Many people in today's world are searching for something. They want to find those things that will sustain them while they are living and giving solid assurances for the afterlife. Even the church leaders of old recognized the need for mankind to seek and find Jesus Christ for that sustaining power during our lives, and the assurance of eternal life after we die.
The points of emphasis which are presented in the answer to the question asked earlier, focus on Jesus and the supportive description of his work on earth. "At the cost of his own blood he has fully paid for all my sins and has completely freed me from the dominion of the devil."
If you have never committed a sin, then you can skip that part. The truth, however, is given in scripture, "We have all sinned and fallen short of the glory of God." So the blood of Jesus, freely given for us, pays for our sins and delivers us from the dominion of Satan. Just that truth should make us shout for joy and devote ourselves to serving the Lord. But there is more.
The life that is devoted to Jesus lives under loving and tender care. That protective care from above is seen in that not even a hair can fall from our heads without the will of the Father. Remember Jesus, in the Sermon on the Mount, talked about this care when he mentioned the lilies of the field and the birds of the air being cared for by God. And if He cares for them, we have his assurance he will care for us.
Because of all these things God does for us through Jesus Christ, the word "therefore" brings us to the final points of the answer. Read again the final sentence, "Therefore, by his Holy Spirit, he also assures me of eternal life, and makes me wholeheartedly willing and ready from now on to live for him." When we consider all that Jesus accomplished throughout his earthly ministry, and ultimately his defeat of Satan and victory over the grave, we can know with great assurance eternal life is ours. I am reminded of Paul writing to the Ephesian church, telling them the Holy Spirit is given to us as a guarantee.
May we remind ourselves daily of the great cost which brought about our salvation, and may we wholeheartedly devote ourselves to live for our Lord. Everything fits into his purpose for our salvation.