Usually, we study yoga step by step, but it is important to remember that all its limbs form a single system, so the true practice of yoga is by no means a linear process. The eight limbs of yoga can make us happy and relieve stress, but they must become an integral part of our life and practice.
The last three limbs (Dharana, Dhyana, and Samadhi) are based on the first five (Yama, Niyama, Asana, Pranayama, and Pratyahara): without harmonious relationships with the outside world, without compassionate attitude towards us, without the stability of posture and breathing, and without the ability to move away from the impact of the thoughts and emotions on us, we will not be able to experience a union with the Divine.
The union with the Divine is not something exceptional - it is potentially available to everyone and at any time. Moreover, each of us has brief moments of insight and inner clarity, when are seized by an eternal feeling of love for the world. So, the yoga practice is one of the most effective tools for achieving it.