What is meant here by "the Calling" is the inner call many human beings in many cultures through the centuries had to dedicate their lives to God and follow a religious life.
In Christianity throughout its roughly twenty centuries, it has had apostles, pastors, bishops, prophets, priests, monks, and nuns (dedicated laity), to highlight most of the manifested roles of the Calling.
In Judaism throughout it history going back as far as the Babylonian captivity, it has had its rabbis, teachers of the Law, scribes, Pharisees, and Sadducees, priests, and prophets.
In Islam throughout its about 1400 years thus far, has had its imams and mahjdis. (Its caliphs, which means "deputy," had the dual political/civil duties and the religious leadership, but emphasis was on civil-political leadership).
Zoroastrianism had its priests and its dedicated laity.
Hinduism has had its priests, ascetics, and lay persons dedicated to the Calling, as has also Jainism, a shoot off Hinduism. And likewise Buddhism, shooting out of Hinduism in Indian, has had its priests and dedicated lay persons.
Taoism (Daoism) has also had its priests and dedicated lay persons who felt and received the Calling. And so also some students of Confucianism.
And similarly, Shintoism has had its priests and dedicated lay persons who felt and sensed the Calling through its hundreds of years of history.
And in parts of the world where indigenous peoples lived, in Africa, Australia, Pacific Islands, and the Americas, there have always been certain people that felt the Calling, understood through their own culture, to dedicate their lives to God, spiritual things, and healing people, from medicine men and shamas, to priests, to prophets, and dedicated lay people.
Let us ask, is there anything in common among all these many people in the various religions and spiritual traditions? I suggest that there are at least two things in common. The more obvious one is that each one basically understood the "Calling" through their culture and their culture's religion/spiritual tradition, based on the knowledge, wisdom, worldview, etc. they were taught by their culture or religious group. The content of what they were taught of course is different for each religion or tradition, but each religion or tradition passed on its beliefs, wisdom, and understanding. While in perhaps a majority of the cases of those who have received the "Calling," which never a study could be done to document all the human beings throughout history who have experienced and lived the "Calling" of course, but I would surmise that for a majority of them, the Calling they received was assisted by mentors, tutors, teachers, or significant other religious or spiritual leaders, either directly, say one-on-one or teacher-students model, or indirectly. But there are no doubt cases where a person received the Calling as if it came directly from God, without the assistance of other human beings, so claimed. Two classic cases here are of course the apostle Paul of Christianity (New Testament) and Mohammed, the great Prophet of Islam. But whether there were other human mentors involved or not in a person receiving the Calling, I submit the SECOND thing all have in common, among all who have sincerely felt the Calling, excluding others such as charlatans or those ambitious for power seeking it through spiritual leadership offices, that they ALL felt and received an INNER Calling, within their own being, soul, and heart, all perhaps connected with the Divine. (We will of course exclude any possible cases of demonically-induced Callings deluding the recipients.)
Let us take this a step or two further. Truism 1: All human beings on earth are of the same human nature (physiological, mental, and spiritual: soul/spirit). Truism 2: the one God who created all things in heaven and earth created all humans. Not all, but at least 3 billion people on earth today believe this. By deductive reasoning, then, we conclude that all the people, even perhaps throughout time, who have felt the inner Calling, all have this in common, this inner sense, and perhaps this inner sense has been and still is today much the same sense or feeling. But we don't really know how another person exactly "feels" it, and we can't interview all those in the past whose earthly pilgrimage is ended. So, while they all may have understood the Calling through each their own cultural, religious, spiritual lens, the Calling itself perhaps is quite similar to all peoples who have felt it.
This sense of the Calling has come to people of every generation and culture, I submit. Some of them dedicated their lives full-time and professionally for the Calling, and they may serve as priests, pastors, teachers, or other religious leaders. There are those who have taken the path of ordination. But there are many more who have taken the path of dedicated lay person. Some have been in traditions where certain vows and even life-long commitments are expected, and other traditions, no life-long commitments are expected for lay members. In other words, for the latter, you can quit anytime you want. And they are many others, I suggest, who have felt the Calling either in their youth or adulthood but have lived or been living in the work world, making a living for their family faithfully too. And there are legendary figures such as Merlin the wizard who may have also felt the Calling, if there was an historical person behind the legend, but due to a lust for power and prestige, turned to sorcery and magic.
I write this not as one who has simply studied the various faiths academically and have learned about the Calling from second-hand or third-hand sources. I am one who too has received the Calling, and the days I received the Calling, over twenty years ago, still is very clear to me today. It marked a very distinct turning point in my life and by God's grace, am still on the path of the Calling, although its seems I have had a detour or two along the way. And I have reflected on the Calling over the years, and even wrote a journal entry over twenty years ago describing my experience. I have not pulled out my old journal to re-read. But one thought and conviction I clearly remember writing about then was this: Its based on a passage the apostle Paul writes in one of his letters in the New Testament: "Let each man be persuaded in his own mind." I applied this to the Calling over twenty years ago, beginning with this base of understanding or assumption that a true God is actually Calling a particular individual person to a dedicated life serving God, because God is God, no human being, nor any human institution or even government can nullify God's Calling to an individual. I want to be careful here, knowing a possible dangerous misconstruction of this that any self-acclaimed religious nut can make some wild assertions. No. God has given human reason to us all. Actually, I recall from my journal entry that I only mentioned other human beings, not institutions. In my life-context at that time, I was thinking about my parents in particular whether they would support me or not. But I also had another experience with a new group of Christians the previous year or two who directly, personally, denied that I was a Christian and stated to my face that my infant baptism was invalid. Well, I knew this was a cultish-type group that was disconnected from historic Christianity, perhaps in everyway. But the conviction that developed in me through this experience was "how dare a supposed Christian brother or sister deny another Christian that they are a Christian, if they confess the Lord Jesus Christ?"
Let us apply this to the Calling, to the inner, you might say, existential Calling, a fancy way of saying, in a real, existing, living, feeling human being. No other human being has the right to deny that Calling in the other.
But, for those who are Christian, of course, and who know the Word, this gets balanced with John's apostolic exhortation to "test the spirits," for not all "spirits are from God.
So practically, if another person believes they have the Calling, encourage them, and guide them along if you are in the position to do so. Observe them and their lifestyle. If there are some corrections that you think need to be made, make them lovingly.
In conclusion, a couple of the purposes of this article is to get a better understanding of the Calling as it has been received in many human beings around the world in various cultures and religious traditions, and to appreciate the Calling. Since my seminary years, when I write about the Calling, for example, when I use it in a sermon, I typically capitalize the C to distinguish it from other types of callings such as simply one person calling to get another person's attention or calling someone via a phone. When we speak of the "Calling," we are speaking of the sense within the inner being of persons to a religious life, which for some is manifest in full-time service. Perhaps this Calling, the inner sense itself is quite similar or essentially the same, but is understood based on their culture, religious upbringing, beliefs, worldview, and practices. In short, the cultural filter may be distinctly different from the many other cultures, but the Calling itself quite similar, based on the assumption of the same God Calling? What will have to be saved for another article is different Callings within the Calling. Some may feel Called to be a prophet, others to be a priest, others to be an apostle or missionary. But that is for another time. I hope this has been helpful to you.
May you truly be blessed!