The word "religion" is very seldom used in the Bible.  Of the three times I found it referenced, two are in the book of James.  Once in James 1:26 and once in verse 27.  James realized  that Christianity was something very, very different from Judaism, and tried to define some basic behaviors that any religion

should produce in the lives of its followers.   He was primarily speaking to Jewish converts. 

James 1:26 "If any man among you seems to be religious, and doesn't bridle his tongue, but deceives his own heart, this man's religion is vain."

James 1:27  "Pure religion and undefiled before God and the Father is this,  To visit the fatherless and widows in their affliction, and to keep himself unspotted from the world."

I think that James was correct about the necessity for a few identifying  characteristics  that any religion should have.

1.  You know when to keep your mouth shut.  I got on one of my daughter's horses a few months ago and was able to lead him where I wanted him to go because of the bridle in his mouth.  God needs to be in the saddle of  your life and you need a bridle in your mouth.

2.  You attend to the needs to those who are in need:  those who are sick, those who are homeless, and those who are alone.   

3.  You live differently (unspotted) from the world.

But religion in itself isn't enough for salvation.  You must give the saddle to God.  You must accept the bridle.  When you truly give yourself to Christ, you have the heart to do his will.  The Holy Spirit.

There is nothing worse than getting on a bucking horses that won't do your will.   They aren't worth anything to the rancher until they have a heart to do the master's will.