Bi-lal kaifa is a ritual intonation of the Fremen.
"Bi-lal kaifa", in Chakobsa, translates to "without qualification".
It is used similarly to the Christian "Amen!" or the Battlestar Galactica "So say we all!". It can also be used as a sort of catch-all phrase, similar to the Italian-American slang "Forget about it", in that its meaning changes by the context it is used. It could be used as a battle cry or challenge, as a means to silence someone similar to "say no more", or expressing severely negative disbelief or revulsion like "I want no more of this!" or "I'll have no part in this!".
Behind the ScenesEdit
Bi-lal kaifa is Arabic, بلا كيف, roughly: 'without asking how' or 'without [knowing] how'. It was a way of resolving theological problems in Islam over apparent contradictions in verses in the Qur'an by accepting without questioning. In Islamic theological discourse, it refers to an ancient dispute on the attributes of God (e.g. face, hand, ...etc.), and how different groups interpreted them. Another was the question of how the Quran could be both the word of God, but never have been created by God because (as many Hadith testified) it has always existed. The traditionalists (e.g. Ash'ari) chose to accept them as is, 'without how'. The rationalists (e.g. Mu'tazili) chose to interpret them allegorically. The phrase Bi-La Kaifa means "without a how". This term is not used often in modern times, except in theological circles. It is amazing that Frank Herbert would be exposed to this term, and make use of it.
Another possible literal definition could be "Any other explanation is useless".