We are saved unto good works, but what is the catalyst for one using their body as a living sacrifice? Gratitude. From whence does this appreciation rise? The grace of God, whereby men in chains are shackled to death, but does God set them free giving them eternal life (undeserving). It is in this state of inadequacy, broken, and helpless, found wanting, that God lifts them up off the floor of humility, agreeing with God that they have fallen short, and seats them with Christ in heavenly places. No longer lost, but found, made a child of the Most High. One of the redeemed.
Grace then is the catalyst to change. Why use grace? For those that are forgiven much, love much (Luke 7:36-50). This being true, and we being saved unto good works, it inspires the lover of God to walk in His will as that living sacrifice. It is the least that we could do, yet so, it is our desire from a place of gratitude found in the foundation that is Christ and Him crucified paying our penalty and us being saved not by merit but grace and mercy.
Luke 7:36-50 King James Version (KJV)
36 And one of the Pharisees desired him that he would eat with him. And he went into the Pharisee's house, and sat down to meat.
37 And, behold, a woman in the city, which was a sinner, when she knew that Jesus sat at meat in the Pharisee's house, brought an alabaster box of ointment,
38 And stood at his feet behind him weeping, and began to wash his feet with tears, and did wipe them with the hairs of her head, and kissed his feet, and anointed them with the ointment.
39 Now when the Pharisee which had bidden him saw it, he spake within himself, saying, This man, if he were a prophet, would have known who and what manner of woman this is that toucheth him: for she is a sinner.
40 And Jesus answering said unto him, Simon, I have somewhat to say unto thee. And he saith, Master, say on.
41 There was a certain creditor which had two debtors: the one owed five hundred pence, and the other fifty.
42 And when they had nothing to pay, he frankly forgave them both. Tell me therefore, which of them will love him most?
43 Simon answered and said, I suppose that he, to whom he forgave most. And he said unto him, Thou hast rightly judged.
44 And he turned to the woman, and said unto Simon, Seest thou this woman? I entered into thine house, thou gavest me no water for my feet: but she hath washed my feet with tears, and wiped them with the hairs of her head.
45 Thou gavest me no kiss: but this woman since the time I came in hath not ceased to kiss my feet.
46 My head with oil thou didst not anoint: but this woman hath anointed my feet with ointment.
47 Wherefore I say unto thee, Her sins, which are many, are forgiven; for she loved much: but to whom little is forgiven, the same loveth little.
48 And he said unto her, Thy sins are forgiven.
49 And they that sat at meat with him began to say within themselves, Who is this that forgiveth sins also?
50 And he said to the woman, Thy faith hath saved thee; go in peace.
His love is not only the means by which our love reciprocates towards Him, but outflows into our lives as we walk in the good works He has prepared beforehand.