When ever I see an individual that is suffering and I am able to tolerate their suffering, is also when I seem to learn and grow the most. Spiritual leaders get me on the path but the so called 'bad people' or 'obstacles' seem to teach me the most. Can Buddhists scriptures explain this? Many thanks.
Suffering is like the fertilizer for our spiritual growth. It is what drives people into religion and spirituality.
If one is happy and content in life one sees no reason to change anything in ones life.
If one experience pain and suffering one naturally wants to seek a solution. For a lot of people that means coming to religion or spirituality to find a way out of their problems.
When meeting a spiritually developed being one knows that this being has gone through suffering and come out on the other side.
Regarding "bad" people or obstacles as vehicles for developing knowledge. It might be because these phenomena obviously show the suffering inherent in them, thereby making them good teachers.
"Pleasant" phenomena can be teachers too but here the suffering is masked. This makes them important to reveal and understand. The Buddha called this "flower-tipped arrows". Picturing a bhouket of flowers with arrow heads underneath so when one tries to pick a flower one is stung by the arrow. In the same way pleasant phenomena cause suffering when they change and disappear due to their impermanent nature. If one had attachment towards them one is left with suffering and a craving for more. That is how addiction is born.
For references to the texts we have The Four Noble Truths. They are briefly:
"The Truth of Dukkha is that all conditional phenomena and experiences are not ultimately satisfying;
The Truth of the Origin of Dukkha is that craving for and clinging to what is pleasurable and aversion to what is not pleasurable result in becoming, rebirth, dissatisfaction, and redeath;
The Truth of the Cessation of Dukkha is that putting an end to this craving and clinging also means that rebirth, dissatisfaction, and redeath can no longer arise;
The Truth of the Path Of Liberation from Dukkha is that by following the Noble Eightfold Path—namely, behaving decently, cultivating discipline, and practicing mindfulness and meditation—an end can be put to craving, to clinging, to becoming, to rebirth, to dissatisfaction, and to redeath".