At Sāvatthi.

"Bhikkhus, cultivate collectedness (stability of mind, mental composure, a concentrated mind). A bhikkhu who is collected discerns as it truly is. What does he discern as it truly is?

[1] ‘This is suffering,’ he discerns as it truly is;

[2] ‘This is the arising of suffering,’ he discerns as it truly is;

[3] ‘This is the ending of suffering,’ he discerns as it truly is;

‘This is the way of practice leading to the ending of suffering,’ he discerns as it truly is.

Cultivate collectedness, bhikkhus. A bhikkhu who is collected discerns as it truly is.

Therefore, bhikkhus, effort should be made to fully understand [4]: ‘This is suffering’;

effort should be made to fully understand: ‘This is the arising of suffering’;

effort should be made to fully understand: ‘This is the ending of suffering’;

effort should be made to fully understand: ‘This is the way of practice leading to the ending of suffering.’"

[1] Suffering (dukkha) can be mild or intense, slow fading or sharp, or in the form of discomfort, pain, dis-ease, unpleasantness, stress, discontentment, or dissatisfaction. Any experience of these should be seen and understood as dukkha.

[2] The arising of suffering points to the source of stress, or the cause of discomfort - the mildest of suffering to start being experienced.

[3] The ending of suffering is the total ending of the experience of both intense and mild suffering, the ending of the experience of discomfort, pain, dis-ease, unpleasantness, stress, discontentment, and dissatisfaction.

[4] To fully understand is a gradual process. It starts with understanding in principle, in theory, in concept, to then an attitude and a way of attending to discern the noble truths in each moment, to gradually having a breakthrough of full understanding, realization of the four noble truths.

Related Teachings:

The effects of cultivating the eightfold path are gradual (DhP 273) - The noble eightfold path is a comprehensive collection of training guidelines that one should practice for the ending of the unwholesome mental qualities and for the benefits of enlightened mental qualities shine through.

Gradual Training, Gradual Practice, and Gradual Progress (MN 107) - The gradual training guideline teaching of the Buddha is how a student starting out in the teachings of the Buddha should gradually practice in to see gradual progress towards breakthrough of fully understanding the four noble truths.

A handful of leaves 🍃 - Essential Teachings of the Buddha to Understanding The Four Noble Truths - A collection of teachings of the Buddha to understand the four noble truths in principle.