Do you need a commentary on the Apostles’ Creed?  Here is over 35 of them from reformed history:

Commentaries on the Apostles’ Creed

One doctrinal topic that is discussed in such commentaries that is not so commonly treated of elsewhere is the Communion of Saints.  The communion of saints is not primarily conversing over a pot-luck with Christians, but entails our spiritual union and fellowship with the whole of Christ’s one Body, the Church, in heaven and on earth, in all places and all times.

On the Communion of the Saints

Enrich your understanding and enflame affections and desires for fellowship with fellow Christian believers, and be sure to check out the sections that:

The Communion of the Saints is Trans-Spatial & Trans-Temporal