Realisation is first hand experience of the Absolute Truth. The goal is not impossible to reach but the journey is long and arduous even for the determined seeker, say the sastras, pointed out Swamini Satyavratananda Saraswati in a discourse. The Gita shows the efficacy of the paths of karma, jnana and bhakti, each of which is useful to the aspirant. Worship of God through puja, japa, dhyana, etc, are advised to be incorporated as one’s daily duties, as these are sure to instil bhakti and jnana.
In addition, to reap the full benefits of spiritual realisation, sravana, manana and nidhidyasa are to be practised. Sravana is listening to explanations on the scriptures and discourses on the Puranas and the Itihasas. It slowly makes untold impact on the listener when at some point of time what is heard enters the heart and mind and stirs the spiritual seeking. In due course, sravana morphs into manana. The student goes over in his mind what has been heard and tries to reason out the validity of it. In this world when the attractions and distractions are strong on the individual, it is difficult to be at these practices. Every single spiritual effort is valuable and is reckoned as the sadhana for the individual. It is carried over to future births until perfection is attained. This is the reason behind the varied levels of spiritual leanings in individuals. Some might have gained proficiency in sravana alone and will continue with manana while those who have mastered these practices begin with nidhidyasa in their next birth.
The Aitareya Upanishad speaks of Vamadeva who gains realisation even when in the womb. It shows that he had to be born to complete whatever nidhidyasa was remaining. Among countless aspirants may be one strives to gain jnana and even for him it may take many births for the jnana to become an inner awareness.