"What does it mean to receive a holy calling?" That's a good question! Whereas "holy" is an adjective, describing the just and loving character of God, a "calling" is the activity by which we are encountered by God in a way which transforms ourselves and our reasons for being. The image associated with a calling is an invitation to come and join another person in a task and into a personal relationship. Notice how a calling is the opposite of a command or an order. An order sends someone away with a task to be completed (Keleuo). A calling, however (Kaleo), invites the called to join the caller in partnership. Out of the relationship between partners, then, emerges a sense of mission and the empowerment with which to effect it. Every spiritual calling is founded upon a spiritual encounter between ourselves and God. And, every spiritual encounter becomes a divine calling with a mission to be carried out. Spiritual encounters and holy callings are inextricably entwined. One cannot exist without the other coming into being.
Anderson, Paul N., "Receiving Holy Callings, and Being Wholly Responsive" (1985). Faculty Publications - College of Christian Studies. 281.