Question

How did the forces of Parliament benefit from having Calvinists on their side? What unique quality did the Calvinists have that proved helpful?

Answer 1

The Parliament managed a Westminster assembly in exchange of the Scottish Covenanter's military service. Their intention was to form the nation together and restore the monarchy. Calvinists are God-centered, this has helped them because as they form the nation, a lot of support was given to the Church.

Answer 2

The Parliament managed a Westminster assembly in exchange of the Scottish Covenanter's military service. Their intention was to form the nation together and restore the monarchy.  Calvinists are  God-centered, this has helped them because as they form the nation, a lot of support was given to the Church.