Ilme Baatin Hamchu masqa, Ilme zaahir hamchu sheer
Ke Buwad sheer masqa, ke buwad be Pir, Pir
Internal Knowledge (ilm baatin) is like butter and External Knowledge (ilm zaahir) is like milk. Like butter cannot be acquired without milk, so to recognition of Allah (ilm baatin) cannot be obtained without a Spiritual Guide.
-Moulana Rumi (rahimullah)