We are called to love one another and to receive with kindness those who live on the margins, Callam says.
Even a cursory examination of the Bible will fill the mind of an enquirer with a panorama of virtues that can transform the landscape of human experience if they are practiced.
One of these virtues is hospitality to strangers.
The Old Testament contains many stories that reveal both the wonder and the joy of welcoming strangers.
Remember, for example, how at Mamre, Abraham and Sarah received three men whom they did not know and served them joyfully (Genesis 18:1-10).
Many pieces of legislation in the Old Testament show how the alien, the sojourner, the stranger should be treated.
For example, Deuteronomy 10:18 asks for them to be clothed and fed, and Deuteronomy 1:16 and 27:19 and Leviticus 19:33 ask for their judicial rights to be respected.
When one turns to the New Testament, one discovers a similar focus on receiving strangers gladly. Many stories teach the importance of the virtue of welcoming those we know and those we do not know and also those from whom we are estranged.
Consider, for example, the parables Jesus told of the Prodigal Son and the Good Samaritan. Hardly can we miss the call to hospitality that is one of the lessons of these parables.
We are called to love one another and to receive with kindness those who live on the margins.
Consider how Jesus models this hospitality in the way he includes, within the circle of his loving concern, those who are normally excluded. He reaches out to embrace and help those who are neglected, overlooked, ostracized or shunned.
This "friend of publicans and sinners" (Matthew 11:19), this man who "welcomes sinners and eats with them" (Luke 15:2) is not surprisingly dubbed "the man for others."
In Scripture, the stories calling us to loving embrace of the stranger are complemented by specific teachings concerning the importance of welcoming strangers.
Deuteronomy 10:19 commands, "You are to love those who are aliens, for you yourselves were aliens in Egypt."
Influenced perhaps by the story in Genesis 18, the author of the Book of Hebrews urges Christians not to forget to "entertain strangers, for by so doing, some people have entertained angels without knowing it" (Hebrews 13:2).
In Romans 12:13, Paul admonishes, "Share with God's people in need. Practice hospitality."
Jesus' parable of the last judgment heaps praise on those to whom the following words can be addressed, "I was a stranger and you welcomed me" (Matthew 25:35).
Furthermore, Jesus teaches us to love one another and he insists that this includes those from whom we are estranged because of problems of historic, culture and negative experiences.
Of course, the Bible is not simply a rulebook with regulations to be obeyed. However, since it opens up for us a window into the nature of God and shows us the kind of people God wants us to become, what it teaches about the right attitude to the stranger should not be overlooked.
Even when our witness to this truth may be rejected by some who find awkward the timing of our testimony, we have an obligation to bear witness to the truth revealed to us in sacred Scripture.
Hospitality to strangers links us both with God and with others. It is a wonderful way of experiencing the presence of the Holy One. Often, it reveals appropriate awareness of our own family history.
How wonderfully has Henri Nouwen given expression to the call to Christian hospitality when, in his book "Reaching Out: The Three Movements of the Spiritual Life" (1975), he prophetically stated, "Our society seems to be increasingly hard and full of fearful, defensive, aggressive people anxiously clinging to their property and inclined to look at their surrounding world with suspicion, always expecting an enemy to suddenly appear, intrude and do harm."
But still - that is our vocation: to convert the "hostis" into a "hospes," the enemy into a guest, and to create the free and fearless space where brotherhood and sisterhood can be formed and fully experienced.
Neville George Callam, a Jamaican, has been serving as general secretary and chief executive officer of the Baptist World Alliance since his election in Accra, Ghana, in 2007. A version of this article first appeared on his blog. You can follow BWA on Twitter @TheBWA.