The Bible doesn’t really use the term “legalism”. The bible uses the word “works”, but it basically means the same thing. It’s really critical that we understand God’s system of grace and faith, and how it differs from a meritorious / works approach to God. Grace “works” by faith, and Merit systems “work” by effort, work and personal merit.
It’s important when reading the bible to understand that both systems, the works/merit system, and the grace system are presented and even “legitimized”. We can come to God on a principle of works, or we can come to him based on grace. The Bible even instructs how to do both!
This can be a source of confusion for us if we do not understand that the Bible presents the works system not because God expects that it can “work” for us – but to engage our effort – to get us to “try it out”, so that through our own failures God can reveal our complete inability, and to show us our need for His grace system. When we learn through the works system how ruined our fallen nature is because of its indwelling sin principal, we are prepared to really understand the grace system, and to really appreciate and treasure it. (Two good books on this subject: Andrew Murray’s Two Covenants, and Watchman Nee’s Normal Christian Life).
We have basically two kinds of responses to God: faith, or a works system. How we respond to God depends on how we view Him. As we become more and more clearly focused on grace, our spontaneous response is faith (and thanksgiving). A thankful, believing heart is the foundation for all Christian virtue. In all of the admonitions in the epistles which are written to believers, it is assumed that all of the good that flows from believers comes from a heart full of faith in thanksgiving.
Works is an Exchange System
The alternative to grace is a works system. If we are not clear about grace, we will automatically approach God with work in an attempt to “merit” something. By works, we attempt to get God to do something for us. We attempt to operate by a principle of exchange. If I do this or that, God will respond to me this way. This can be either outward works (helping the poor, going to church, giving money) or deep, heartfelt inward works, (like sorrow over sin and weeping over our personal condition .)
Perhaps in exchange for outward works we expect God to look more favorably on us – to bless our situation, or to give us advancement or promotion, or simply to bless us with His presence. In exchange for our inward weeping and repentance, perhaps we expect that He will relent and forgive us of some sin.
In this kind of exchange system we do works that are apart from faith in what God has accomplished in Christ – in fact they typically ignore what God has accomplished in Christ. These works do not flow from a heart of thanksgiving based on a view of what God has accomplished for us in Christ. They actually flow from a fearful heart of unbelief, a heart that is not at all focused on what God has revealed of Himself and His purpose and work in Christ. The bible calls them “dead works”, because they’re useless. Not only are they useless but they tend to deaden us inside because they keep us from freely coming to the Living God.
Qualifier – good works vs. dead works
In case it’s not clear, in this context when I speak of works I mean what the bible calls “dead works” (Hebrews 6:1) or “works of the law”. These are works done with the intention to gain position before God or merit blessing from Him. The New Testament speaks much of good works, that can be an evidence of salvation, and are done from a thankful heart full of faith. The purpose of good works are to adorn the gospel and to show love. They flow from a heart that’s already satisfied that I am accepted in Christ. Making good works a requirement for salvation rather than an evidence of salvation already received is to put the cart before the horse, at which point they become dead works.