>Ulla said, Let him [Messiah] come, but let me not see him. Rabbah said likewise: Let him come, but let me not see him. R Joseph said: Let him come, and may I be worthy of sitting in the shadow of his ass's saddle. Abaye inquired of Rabbah: What is your reason [for not wishing to see him]? Shall we say, because of the birth pains of the
Messiah?
Sanh 98b