Final answer:
The phrase in question refers to 'pure religion,' which in Christian teaching emphasizes charitable actions and personal piety, highlighting care for orphans and widows as well as keeping oneself morally pure.
Step-by-step explanation:
The phrase 'to visit the orphans and widows in their affliction, and to keep oneself unspotted from the world' is described as pure religion in the context of Christian teachings, specifically within the New Testament book of James. This statement underscores the importance of charitable works and personal piety as hallmarks of a sincere religious practice. It emphasizes that true devotion is demonstrated through compassion for those in distress, like orphans and widows, and maintaining moral purity within oneself amidst worldly influences.