Devotional service is the only absolute and auspicious means of deliverance from the grip of material existence. There are many indirect methods for deliverance from the clutches of material existence, but none of them is as easy and auspicious as bhakti yogaThe means of jnana and yoga and other allied disciplines are not independent in delivering a performer. Such activities help one to reach the stage of bhakti yoga after many years. In Bhagavad Gita, it is said that those who are attached to the impersonal feature of the Absolute are liable to many troubles in the pursuit of their desired goal, and the empiricist philosophers, searching after the Absolute Truth, realise the importance of Vasudeva realisation as all in all after many births.
As far as yoga systems are concerned, it is also said in Gita that amongst the mystics who pursue the Absolute Truth, the one who is always engaged in the service of the Lord is the greatest of all. And the last instruction advises fully surrendering unto the Lord, leaving aside all other engagements or different processes for self-realisation and liberation from material bondage.
And the purport of all Vedic literatures is to induce one to accept the transcendental loving service of the Lord by all means. Prabhupada writes that there are many indirect methods for deliverance from the clutches of material existence, but none of them is as easy and auspicious as bhakti yoga. The process of jnana and yoga eventually will have to lead to bhakti yoga — attraction to supreme personality of Godhead. In this world, in the grip of material existence, we can get entangled in so many forms of knowledge.
But all that knowledge is waste unless it leads one to that Absolute Truth. So in this bhakti yoga different yoga systems are mentioned eventually it is thinking of Krishna.