With regard to the Four Noble Truths we have four functions to perform:

The First Noble Truth is Dukkha, the nature of life, its suffering, its sorrows and joys, its imperfection and unsatisfactoriness, its impermanence and insubstantiality. With regard to this, our function is to understand it as a fact, clearly and completely (parññeyya).

The Second Noble Truth is the Origin of Dukkha, which is desire, ‘thirst,’ accompanied by all other passions, defilements and impurities. A mere understanding of this fact is not sufficient. Here our function is to discard it, to eliminate, to destroy and eradicate it (pahātabba).

The Third Noble Truth is the Cessation of Dukkha, Nirvāṇa, the Absolute Truth, the Ultimate Reality. Here our function is to realize it (sacchikātabba).

The Fourth Noble Truth is the Path leading to the realization of Nirvāṇa. A mere knowledge of the Path, however complete, will not do, In this case, our function is to follow it and keep to it (bḥāvetabba).