"The King is very proud of the mosque, hoping that Istiqlal becomes a symbol of Islam civilization and at the same time peace and harmony," Bahrul said.
He added the King wrote the statement and the hope in the guest book of Istiqlal Mosque.
According to Bahrul, the arrival of the Custodian of the Two Holy Mosques to Indonesia is a symbol of friendship between the country and Saudi Arabia.
The visit to the Istiqlal mosque was part of the King's current state visit agenda to Indonesia.
President Joko Widodo visited Saudi Arabia on September 11, 2015.