Our peace in Christ is not based on a God who in sick sentimentality felt sorry for fallen mankind and decided to overlook our sins.
Jesus promised us His peace even before He died on the Cross:
"Peace I leave with you, my peace I give unto you: not as the world giveth, give
I unto you. Let not your heart be troubled, neither let it be afraid." (John 14: 27)
Yet sin has made us dead in our tresspasses. For sin, there must be a payment:
"For the wages of sin is death; but the gift of God is eternal life
through Jesus Christ our Lord." (Romans 6: 23)
Sin must be punished, but God so loved us, that He sent His Son to die for us, taking the punishment upon Himself for our sins:
"He is despised and rejected of men; a man of sorrows, and acquainted with grief:
and we hid as it were our faces from him; he was despised, and we
esteemed him not.
"Surely he hath borne
our griefs, and carried our sorrows: yet we did esteem him stricken, smitten of
God, and afflicted.
"But he was
wounded for our transgressions, he was bruised for our iniquities: the
chastisement of our peace was upon him; and with his stripes we are
healed." (Isaiah 53: 3-5)
Here, Isaiah prophesied that Jesus not only bore our pains and sufferings, but also he took upon Himself the curse of the law:
"Christ has redeemed us from the curse of the law, being made a curse for us: for
it is written, Cursed is every one that hangs on a tree:" (Galatians 3: 13)
Because of His Finished Work for us, we have peace with God (Romans 5: 1)
More importantly, though, Jesus Christ is our peace:
"For he is our peace, who hath made both one, and hath broken down the middle
wall of partition between us;
in his flesh the enmity, even the law of commandments contained in
ordinances; for to make in himself of twain one new man, so making peace;" (Ephesians 2: 14-15)
We were separated from God the Father because of our sin nature, which we inherited from Adam. Despite our dead state in our trespasses, God sent His Son to die for us, putting to an end once and for all the law, which strengthens sin in man and outlines for him is inherent and essential failure to measure up through his own efforts to God's righteous standing. We have peace with God through Christ Jesus, because He has taken the just punishment for us and has fulfilled the law, granting to us His own righteousness.
Through His Holy Spirit, we are now members of His Kingdom:
"For the kingdom of God is not meat and drink; but righteousness, and peace, and
joy in the Holy Ghost." (Romans 14: 17)
And this peace does not merely provide the believer a ballast in the shocks and storms of life, but also furnishes us with direction in trying times:
"And let the peace
of God rule in your hearts, to the which also ye are called in one body; and be
ye thankful." (Colossians 3: 15)
In this verse "rule" means "preside, as a judge". The peace of God within us allows us to know what path God wants us to take, what decision He wishes us to make. We can sense through His peace whether the action is good or bad, one to take or to reject.
With His peace, we then can pursue peace with others:
"Let us therefore follow after the things which make for peace, and things
wherewith one may edify another." (Romans 14: 19)
This we accomplish by being spirit-led, for one of the fruits of the Spirit is peace (Galatians 5: 22)
Jesus told His disciples that He was leaving His peace with them, and thus with us. In effect, He promised to leave us Himself! Through God's justice, bringing upon His Son all over His wrath for our sins, God enabled His Son to be our peace.