The device is not limited to poetry. The end word of a prose unit is its fāṣilah. If a writer consistently preserves an additional pre-ending sound beyond the correspondence needed for sajʿ, prose too can show luzūm mā lā yalzam.
For example, agreement in the final consonant may already satisfy the basic rhyming requirement; holding another specified preceding consonant constant adds a further constraint.
Sajʿ and iltizām are therefore compatible. The same prose passage may have both a basic rhyme and a more demanding, voluntarily maintained sound pattern.