The contest of the two verses is usually presented as sudden enlightenment defeating gradual cultivation. The history is less tidy and rather more interesting.
Huineng was not, in his own lifetime, the acknowledged sixth patriarch of anything. That claim was made for him a generation later by Shenhui, a formidable polemicist who from the 730s campaigned publicly against the lineage of Shenxiu, gave it the name Northern school, characterised it as gradualist, and installed his own master as the true heir. The campaign worked so completely that the tradition it attacked disappeared, and everything the surviving school said about its rival went unchallenged for a thousand years.
The manuscripts recovered from the sealed cave at Dunhuang in the twentieth century changed that. They include early versions of the Platform Sutra considerably shorter than the received text, showing the work growing over time, and they include writings of the so-called Northern school which turn out not to teach the crude gradualism ascribed to it. Modern scholarship therefore treats the sudden and gradual quarrel as a real doctrinal question that was fought as a sectarian one.
What survives the correction is the doctrine itself, which is genuinely in the text: no-thought as the practice, seeing one's own nature as the goal, and the insistence that meditation and wisdom are not two things done in sequence but one thing seen from two sides.