true religion: Christ's work in us

God speaks through the prophet Isaiah to the nation of Judah in Isaiah 1 and gives a clear summation of the difference between false religion and true religion:  "What to me is the multitude of your sacrifices?...I've had enough of your burnt offerings...the fat of well-fed beasts...I do not delight in the blood of bulls, lambs, or goats...Bring no more vain offerings...Your new moons and your appointed feasts my soul hates...they have become a burden to me" (1:11-14).  This would appear to be harsh from a God who so clearly appointed Israel to practice said sacrifices and feasts.  Why have these practices become such an abomination?  Because of 1:16-17:  "Wash yourselves; make yourselves clean; remove the evil of your deeds from before my eyes; cease to do evil, learn to do good; seek justice, correct oppression; bring justice to the fatherless, plead the widow's cause."  Apparently in the midst of all of the above (former) "worshipful" acts Judah is practicing, they are neglecting  those (latter) obvious social needs, and in turn leaving many people unprovided for, and in need.  This is why God says to take care of THESE things first, before they come back for sacrifice and feasts (Isaiah will conclude this argument in ch 58).
 The clear teaching is that Judah had come to the point of letting their worship be done in ritual, outwardly, while inside their hearts are far from God.  This is why God says in 29:13 "These people honor me with their lips, but their hearts are far from me," which is cited by Jesus in speaking to Pharisees who are exalting their social rules above God's Word (cf. Matt 15, Mark 7).  It's important to remember that God sees people's hearts (see 1 Sam 16:7, Rom 8:27, Heb 4:12-13, among others).  The failure to realize this is the cause for many Christians' misunderstandings about what true worship is, as Judah in Isaiah 1 had misunderstood.  It's not that the worshipful practices (sacrifice, feasts, etc.) are bad--the practices are good...the problem is that that's all they are:  practices; but they're not worshipful anymore (if they ever were).

Inevitably, if left up to their self, every single person on planet Earth will come to the Lord cheaply, in practice, but not in worship.  I believe "these people honor me with their lips but their hearts are far from me" is a summary statement of the Bible's teaching on the state of humanity.  I also believe it's an accurate summary statement for much of the 21st century American Church:  people who honor the Lord with their lips, but have hearts that are far from Him--they're deceived into thinking that their practices make them Christian; but the nature of deception is that many who think they're not deceived actually are still, and God, who sees hearts, is aware of it and isn't deceived (see Matt 7:21-23, John 9:39-41).  We must "examine ourselves, to see if we're in the faith" (2 Cor. 13:5).

This is why the work of the Beloved Son, our Lord, is so important to our state before a holy God.  We could never trick God since He already knows our hearts, and good works never outweigh a bad heart.  Further, we couldn't disappoint Him because to be disappointed is to be let down--God is never let down, because He gains nothing from us.  All of our worship doesn't gain Him--He is exalted ABOVE all of our praise (Nehemiah 9:5). 
The work of Christ is to purify our hearts, and create in us a desire for the glory of the Living God.  The prophets (Isaiah, Jeremiah, Ezekiel, Malachi...especially Mal 3:1-4) bear witness that the Christ's work will be to purify and sanctify the "offerings" given unto the Lord in His Temple.  In Christ, God's people are the Temple (1 Cor. 3:16, 2 Cor. 6:16, Heb 3:6, among others).  Whereas with Israel, worship was something you went to the temple to do, with Christians, worship is something that continually is happening all of the time.  The reason for this is that in Christ, God has "changed our hearts" and "written his law on our hearts" (see Ezek 36 and Jerem 31).  In this way, God is purifying the sacrifices of worship by changing people's hearts.  (Is your heart any different than it was before you were a Christian?  It's not a question of "do you go to church or not?" or "do you know you're going to heaven?", but rather "are you any different?")

By condemning sin in Christ's body, God has "done what the law, weakened by the flesh could not do...in order that the righteous requirement of the law might be fulfilled in us, who walk not according to the flesh but according to the Spirit" (Rom. 8:3-4).  Paul is telling us that in Christ's work, God has ensured followers in this world.  Whereas He initially gave the Law, since man's heart was the problem, Israel couldn't keep up to it.  So in Christ, God MAKES followers who will obey Him and love Him.  We're reminded of John the Baptizer's sobering and humbling words in Luke 3:8, "God is able to raise from these very stones children of Abraham."  God can do what God wants.  He knows more than we know, is more powerful than we are, is more in control than our control is...this is God's world and God can do what God wants, which includes causing people to follow Him in such a way that they won't stop.  And how is this the case?--that He unites them with His eternal Son who has been giving Him glory and honor since the very beginning of time...this Son even prayed that the new worshipers would be united with Him IN eternity, to share the glory that has been between the Father and Son since the beginning (see Jn 17:20-24).  And the world has never seen a more sure-fire pray-er than Christ Himself.

Whereas Israel had failed to obtain "the promise" because of their disobedience and laxness of religion (as spoken of in Isaiah 1), Romans 9 has Paul telling us that this new work enacted in Christ is work that is received by Gentiles (non-Israelites) because Israel has "failed to reach that law...because they did not pursue it by faith, but as if it were based on works" (9:32).
And this is exactly what Isaiah wrote of:  coming to the Temple with polluted offerings, with comatose half-asleep deadness, because they don't love God, but love themselves and their lives more than anything else.  Even their love of God is love of self, because they only seek to get from Him what will benefit themselves (in their own eyes) the most. And since they don't love God, their temple practices are their own way to seek to justify themselves, while God stays at a distance and then owes them heaven after they die.  This is why they couldn't "obtain the promise."

But in Christ, God (again) has "done what the law, weakened by the flesh couldn't do...in order that (we)...walk according to the Spirit."  The very Spirit of the Living God has been placed inside of us--there is a "secret and hidden wisdom of God" which consists of "what God has prepared for those who love him", and "these things God has revealed to us through the Spirit" (1 Cor. 2:7,9-10).  What is this wisdom that is given to us?  It is that Jesus is "the Christ, the Son of the Living God", as Peter said, to which Jesus responded, "flesh and blood has not revealed this to you, but my Father who is in heaven" (Matt 16:16-17).

When you are crushed under the weight of a holy and sovereign God who alone is good (Mk 10:18), who does all things well and right (Deut. 32:4, Dan 4:37), who is in sovereign control of everything (Deut. 32:39, Job 23:13), who sustains everything and holds it together (Job 34:14-15, Heb 1:3) and who has eyes inside your heart (1 Sam. 16:7, Heb 4:12-13) and is able to make a person into a Christian (Lk 3:8, Jn 6:63-70), any pride or arrogance or even laziness that you harbor is crushed as well.  You throw yourself on the mercy and grace that are in Christ Jesus because you love him and hate yourself; you repent of all of your works because all they are is bad and if there are any good, you know it was God's goodness in providence; you call out on the name of the Lord and are saved, because ALL who call on the name of the Lord are saved.  Easily we're reminded of the sinful tax collector from Luke 18 who was in the Temple and only knew one thing to do: put his head down, beat his breast, and cry out "have mercy on me, a sinner".  It's in that place that he (without following any rules) "went down to his house justified" (Lk 18:13-14).
This is because, again, God doesn't delight in burnt offerings and sacrifices.  At least, He doesn't delight in them near as much as "a broken spirit, (and) a broken and contrite heart" (Ps. 51:17), for these are "the sacrifices of God".

And it is from this place that Paul gives the summary challenge in Romans 12:1:  after all of the theology of salvation, with emphases in a) God's absolute sovereignty, b) man's fallenness, and c) Christ's work's sufficiency in justifying them before Him, Paul concludes with, "therefore..by the mercies of God..present your bodies as a living sacrifice, holy and acceptable to God, which is your spiritual worship."  To those who are in Christ, this is the only option.  And those who do this are those who are in Christ.  Wherever Christ is, there is the Spirit; wherever the Spirit is, there is freedom; and wherever freedom is, there is Christ, because if the Son sets you free, "you'll be free indeed". 

This is true religion.