Varna-Yoga
It is interesting to note how well the four varnas match the four broad categorizes of yoga (jnana, raja, karma, and bhakti). Note that none of these were mutually exclusively (in fact in the past all forms of yoga were accompanied by a good amount of bhakti).
It is said that the difference between the kshatriya and brahmin in terms of approach to knowledge is that the former can be single pointedly focused whereas the later is unfocused.
It is such focus that makes a kshatriya out-skill others in things that require extreme focus – like combat sports for example and raja yoga (self-realization), and it is that unfocusedness that makes a brahmin more broadminded and attain self-realization through jnana yoga and bhakti yoga (Sri Ramana Maharshi, Sri Ramakrishna Paramahamsa, Siddhar Bhogar, Adi Shankara, Ramanuja, Madhavacharya, Sri Raghavendra,…).
Thus it shouldn’t come as a surprise that Krishna chose Arjuna as his point of focus, not to mention Krishna, Rama, Buddha, Vishvamitra, Kannappa Nayanar,… some of the most important spiritual figures in Hinduism all started off as kshatriyas (attaining the state of brahmin varna by virtue of self-realization – or simply calling forth their self-realization in case of avatars like Krishna).
Similarly the desire “to do or to make” nature of vaishya varna made them best suited towards karma yoga, and the humility of those of shudra varna made them the best suited to attain self-realization through bhakti yoga. Many great saints and sages have been produced from these varna as well (Tiruneelakanda Nayanar, Nammallvar, Tulsidas, Kabir, Veda Vyas, Valmiki, Narada Muni, Mata Amritanandamayi,…)