The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no warrants shall issue, but upon probable cause, supported by oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.
the phrase belonging to the verb of the fourth amendment is:

Let's find the verbs:

The whole text is like this:

The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures,

no verb so far (at least not in an inflected form)

shall not be violated,  (shall is the verb)

and no Warrants shall issue,
(shall is the verb)

but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.

So the verb is "shall" and the phrase belonging to the verb is "shall not be violated"