It is the letter of James that states that the gathering of a Christian group is referred to as an assembly – the Greek word for assembly is the one from which we derive synagogue.

There is little in this document that is overtly theological, nothing about the death and resurrection of Jesus, nothing about doctrines that are to be believed. Its focus is primarily practical, combining wisdom about how to live and prophetic indictment of how people commonly do live. Half of James’ 108 verses are imperatives.

The author emphasizes the importance of doing and acting. Two of the best known passages are: be doers of the word, and not merely hearers…doers who act and Faith without works is dead. His examples of works are concretely compassionate: clothing the naked, feeding the hungry, supplying their bodily needs.

Wisdom – how to live the way – is a frequent theme in James. One passage contrasts two kinds, the wisdom from above and earthly wisdom. The former, of course, is from God. It is peaceable, gentle, willing to yield, full of mercy and good fruits, without a trace of partiality or hypocrisy, with a harvest of righteousness … for those who make peace. The latter is marked by envy and selfish ambition, leading to disorder and wickedness of every kind.” The contrast is similar to Paul’s contrast between the wisdom of God and the wisdom of this world.

James recognizes that this conflict goes on within individuals, including presumably within the Christians for whom he writes. He speaks of people who are double-minded. The Greek word means to have two minds, two psyches. To play with language, this condition can be called di-psychosis.

In this state people have a divided commitment and thus lack grounding and stability. They are like a wave of the sea, driven and tossed by the wind. James contrasts loyalty to God with friendship with the world: friendship with the world is enmity with God. As James uses the phrase, it does not refer to God’s created world. Rather, it indicts the humanly created world of covetousness and violence – earthly wisdom, the way this world most often is. In this context, he commands: purify your hearts, you double-minded. The choice is friendship with the world or friendship with God.

James also includes harsh indictments of the rich and their position in the world. The first passage speaks of them withering away like beautiful flowers, the second criticizes the favoritism they often receive, and the third indicts them for not paying their workers adequately and living lives of luxury and pleasure, fattening their hearts.
I would strongly recommend my readers to read the Letter of James!