Procul, O procul este profani.
In the name of the Mighty and Terrible One, I proclaim that I have banished the Shells unto their habitations.
I invoke Tahuti [Tehuti], the Lord of Wisdom and of Utterance, the God that cometh forth from the Veil.
O Thou! Majesty of Godhead! Wisdom-crowned Tahuti! Lord of the Gates of the Universe! Thee, Thee, I invoke.
O Thou of the Ibis Head! Thee, Thee I invoke.
Thou who wieldest the Wand of Double Power! Thee, Thee I invoke!
Thou who bearest in Thy left hand the Rose and Cross of Light and Life: Thee, Thee I invoke!
So begins Liber Israfel (LXIV) from number 7, volume 1 of The Equinox. What a lot of people do not know is that the source of this ritual is not Crowley, but Alan Bennett who performed it in a ritual alongside Florence Farr.
The original invocation starts:
Majesty of Godhead, Wisdom crowned Thoth, Lord of the gates of the universe: Thee! Thee we invoke! Thou that manifesteth in thy symbolic form as ibis-headed one: thee, thee we invoke! Thou who holdest in thy hand the magic wand of double power: thee we invoke! Thou who bearest in thy left hand the rose and cross of light and life: thee, thee we invoke!
The original working was done on 13 May 1896, six years before the version in the Equinox was published, and a year and a half before Crowley was initiated as Neophyte in the Order of the Golden Dawn.
The original working was the famous Taphthartarath (Mercury) ritual, the evocation of the spirit into visible appearance. More details about the ritual can be found in Talismans and Evocations of the Golden Dawn by Pat Zalewski.
(There is another source that I can not remember off the top of my head.)