The Rev. Jan Zotter told a funeral audience Saturday that Logan Stevenson's life "had an impact over the whole world."
About 75 family and friends attended the service at the Mason-Gelder Funeral Home in Jeannette, about 25 miles east of Pittsburgh, The Pittsburgh Tribune-Review reported.
Christine and Sean Stevenson had planned to marry next year but moved the ceremony to Aug. 3 so their son could participate after the couple learned he had weeks to live.
The child, who died Monday night in his mother's arms, had leukemia and other medical complications, including a mass on his remaining kidney.
"He was a fighter," said Seth Antoniak, who was with Logan and the couple as they exchanged vows. "He was 2 and had everything thrown at him."
Some people attending the service left notes with pictures of Logan on poster boards bearing such headings as "Sweet Baby," ''We Miss You Already" and "The Best Man."
"Even though it was heartbreaking to let you go, Heaven is very lucky to have you," said a note from Logan's grandparents, Debbie and Larry Stevenson.
Zotter said that when a child dies, everyone asks why. But such questions are "mysteries of God that we can't fathom," she said. She assured the boy's relatives and friends that they will one day understand the reason, when they are reunited with him.
"Logan is with God, the Father," Zotter said. "I bet he's playing baseball. I bet he's seeing the horses there."
Information from: Pittsburgh Tribune-Review