The leaders of three major Christian churches—Pope Francis, Ecumenical Patriarch Bartholomew, and Greek Orthodox Archbishop Ieronymos II—united in a dramatic show of Christian unity, meeting on Saturday on the small Greek island of Lesbos to see for themselves the plight of hundreds of thousands of mostly Syrian refugees stranded there.

Seeing the anguish of the refugees inside prison-like camps, the three Christian leaders issued a joint warning to European leaders that they face God's judgment for their action, reminding them of what Jesus said in Matthew's Gospel: "Assuredly, I say to you, inasmuch as you did it to one of the least of these my brethren, you did it to me."

The three leaders made their intensely emotional visit less than a month after the European Union began deporting refugees awaiting asylum hearings in Lesbos back to nearby Turkey, according to the National Catholic Reporter.

Many of the refugees cried openly upon seeing the three Christian leaders. One man collapsed at the Pope's feet, shaking while he cried for a blessing. A woman pleaded for medical care for a daughter with bone cancer.

Several others grabbed Pope Francis' arms, hands and feet, screaming out prayers and calls for help.

In their joint declaration, Francis, Bartholomew and Ieronymos say they had traveled together to demonstrate "profound concern" for the migrants' treatment.

"The tragedy of forced migration and displacement affects millions, and is fundamentally a crisis of humanity, calling for a response of solidarity, compassion, generosity and an immediate practical commitment of resources," they state.

"From Lesbos, we appeal to the international community to respond with courage," they continue. "We call upon all political leaders to employ every means to ensure that individuals and communities ... enjoy the fundamental right to live in peace and security."

Speaking to the refugees, Pope Francis said: "I have wanted to be with you today. I want to tell you that you are not alone."

"I have come here with my brothers ... simply to be with you and to hear your stories. We have come to call the attention of the world to this grave humanitarian crisis and to plead for its resolution."

"God created mankind to be one family; when any of our brothers and sisters suffer, we are all affected," the Pope said.

Bartholomew said: "We promise that we shall never forget you. We shall never stop speaking for you. And we assure you that we will do everything to open the eyes and hearts of the world."

The Pope and the two Orthodox leaders then offered a joint prayer for all the victims who have died at sea attempting to reach the island. The prayer ended:

Merciful God and Father of all,

wake us from the slumber of indifference,

open our eyes to their suffering,

and free us from the insensitivity

born of worldly comfort and self-centeredness.

Inspire us, as nations, communities and individuals,

to see that those who come to our shores are our brothers and sisters.