While public divine revelation ended with the end of the New Testament, God still inspires his people in a variety of ways.
In particular, the saints are those men and women whose lives are worthy of imitation and who strove with all of their might to be attentive to the movements of the Holy Spirit.
The saints show to us how the Holy Spirit does not always work the same in every individual and often inspires holy men and women to seek God in creative ways.
The Catechism of the Catholic Church explains how the saints provide for us different schools of Christian spirituality:
In the communion of saints, many and varied spiritualities have been developed throughout the history of the churches. The personal charism of some witnesses to God's love for men has been handed on, like "the spirit" of Elijah to Elisha and John the Baptist, so that their followers may have a share in this spirit. A distinct spirituality can also arise at the point of convergence of liturgical and theological currents, bearing witness to the integration of the faith into a particular human environment and its history. The different schools of Christian spirituality share in the living tradition of prayer and are essential guides for the faithful.
To put it more eloquently, the Catechism describes them as "refractions" of the light of God:
In their rich diversity they are refractions of the one pure light of the Holy Spirit.
The key is to see the saints and their teachings as refractions that always trace their source to God.
They are not themselves the source of the light, but only reflect it in a particular way
Whenever the Church recognizes a saint's holiness and approves their spirituality, we can be assured that they were vessels open to the inspiration of the Holy Spirit.
