The Prayer to the Cloud of Unknowing is performed by Humanoid Cylons when they believe that that downloading is impossible and death is near.
Several Cylons, all infected by a contagion found on an ancient beacon, crawl to each other on their stricken basestar to say the prayer.
The prayer, interrupted by shouts of the Colonials as they assess the situation of living Cylons in their midst is: "Heavenly father [. . .] grant us the strength...the wisdom [. . .] and above all...a measure of acceptance..."
Lee Adama learns of this prayer from Sharon Agathon and witnesses the event (A Measure of Salvation).