Kingdom values have helped bring radical transformation in society precisely when Christians understood their calling to be salt and light in the public square.
The number of people fleeing war, persecution and conflict exceeded 70 million globally last year. Churches worldwide will celebrate World Refugee Sunday on June 23.
Authorities gave no reason for arresting the 13 Christians, except to say that they were all converts from Islam.
For the first time,Transparency International has also examined the relationship between corruption levels and the degree of freedom enjoyed by media and civil society groups.
Since 2012, Sudan has expelled foreign Christians and bulldozed dozens of church buildings on the pretext that they belonged to South Sudanese.
More than 60% of the 176 countries analysed have serious corruption problems. This year, the index highlights the connection between corruption and inequality.
More than 150 died last week in fight between President and Vice President rival armies. Sudanese Christians are being targeted.