Popular Christian blogger Tim Challies has paid a touching tribute to his "dear" son Nick after he tragically died on Tuesday. 

Nick, 20, was playing a game with his sister, fiancée, and several other students at a park near the campus of Southern Seminary in Louisville, Kentucky, when he collapsed.

Despite the efforts by emergency personnel, he could not be revived. 

Nick was a junior at Boyce College, a Southern Baptist institution and the undergraduate division of Southern Seminary. His sister, Abigail, and fiancée, Anna Kathryn "Ryn" Conley, both attend Boyce.

In a statement, the college said the cause of death remains unknown but is not related to Covid-19.

In a moving tribute on his blog, Tim said he had lost "my dear son, my sweet son, my kind son, my godly son, my only son".

"Aileen and I cried and cried until we could cry no more, until there were no tears left to cry. Then, later in the evening, we looked each other in the eye and said, 'We can do this.' We don't want to do this, but we can do this—this sorrow, this grief, this devastation—because we know we don't have to do it in our own strength," he wrote. 

"We can do it like Christians, like a son and daughter of the Father who knows what it is to lose a Son." 

He asked for prayers for the family as they continue to grieve. 

"We know there will be gruelling days and sleepless nights ahead. But for now, even though our minds are bewildered and our hearts are broken, our hope is fixed and our faith is holding. Our son is home," he said. 

Boyce College founder Albert Mohler said Nick was an "outstanding young man, faithful to Christ, who was also a friend to all." 

"He was a much loved and important part of the Boyce College family. We are thankful to have known him, and so very thankful that he came to be a student at Boyce College. He made us all proud. No one saw this coming," he said. 

"Our love and prayers and shared experience of shock are transformed into heartbreak for Nick's sweet parents, Tim and Aileen Challies, and for his sisters, Abigail and Michaela.

"How can a loving mother and father bear this pain, but by God's mercy? His sweet sisters are bearing a pain only they can know. We are carrying them all in our hearts.

"In the mystery of God's infinite kindness, brothers and sisters in Christ know that our earnest prayers and anguished sympathy really do matter to us in a time of grief and trial. They matter to us because we matter to God. We are praying that our love will comfort the Challies family and Ryn as they walk through these days.

"Right now, none of us can think of Nick's death without a sense of unreality, but death is real. Yet, we know that the love of Christ is more real than anything - infinitely greater than the combined energies of the cosmos. Far greater than the power of death."

The Challies travelled through the night from their home in Canada to attend a gathering at the college on Wednesday to mourn the passing of their son. 

Addressing the gathering, Boyce College Dean Dustin Bruce said: "There are times and there are occasions in the life of a community like this when the fallenness of our world breaks in [and] we experience brokenness and sorrow afresh.

"This morning is one of those times. There are no good explanations. There are no good platitudes that suffice. But there is Christ and he is all-sufficient.

"It's right to grieve, but we do not grieve as those who have no hope. We mourn the loss of Nick, but we mourn knowing that when Nick left us, he went to be with the Lord. All of us who are in Christ will one day see him again."

Speaking at the gathering, Tim said Nick had "loved" the college, and its students and faculty. 

"Thank you for being his teachers, his mentors, his friends, and his family when he was here in America," he said.

"He ran only a short race, just 20 years, but he finished strong. I'm thankful he was able to finish his race surrounded by the people he loved, surrounded by you."

A formal memorial service will be held on the campus of Boyce College at 11am on Friday.