Bible is a supplementary a treatise written by an enlightened one. In Hinduism sacred texts are full of them. Above 200 Upanishads (independent spiritual treatises) existed in Hinduism, every single one of them compiled and written by sages and Rishis who in their lifetime succeeded in reaching stage of enlightenment.
Everything contained in Bible exists in Bhagavad Gita but not everything contained in Bhagavad Gita exists in Bible. Reason is apparent. The preceptor Jesus Christ gained his entire wisdom indulging in sacred texts like Bhagavad Gita, Upanishads even Vedas. During the missing years in his life (age 14 to 29) Jesus Christ came to India to indulge in sacred texts.
The entire wisdom of Jesus Christ is owed to Hinduism scriptures like Bhagavad Gita and Upanishads.
It can rightly be said that every sacred scripture available in this world emanated from Vedas, Upanishads and finally Bhagavad Gita. Even all enlightened ones like Mahavira, Gautama Buddha, Jesus Christ and Prophet Mohammed owed their wisdom to teachings of Lord Krishna contained in Bhagavad Gita.
There was nothing more pure, subtle than teachings of spirituality contained in Bhagavad Gita. The teachings of Bhagavad Gita form summum bonum of spirituality.
Furthermore Hinduism does not have one single book from where percolated all Hindu wisdom.
All four Vedas, above 200 Upanishads and gist of Bhagavad Gita collectively forms sap of spirituality contained in Hinduism religion. Other than these scriptural texts there were many Itihasas, Puranas and other spiritual literature for serious seekers to indulge.
The doctrine of Anekantavada and Syadvada by Mahavira were exemplary.
The doctrine of Advaita Vedanta and precept of Maya (veil of illusion) by Adi Shankaracharya also had no parallel in mankind.
In Hinduism there is no dearth of spiritual literature, sacred texts highlighting virtues of spirituality, explaining all hidden underlying fundamentals of life in stages.
Vedas (Hinduism revelations) form first words of God invoked by sages and Rishis of different times. After Vedas came Upanishads followed by Bhagavad Gita!
But one thing in Hinduism is very unique. Only by indulging in teachings contained in Bhagavad Gita any human being world over belonging to any religion, Faith or belief can ceremoniously indulge in teachings of Lord Krishna in Bhagavad Gita to reach state of enlightenment. One can do this even while following ones religion.
The teachings contained in Bhagavad Gita had universal appeal. Anyone who was truthful 100% could easily follow it. Another ingredient necessitated to follow contents of Bhagavad Gita was 100% faith in existence of God and world of souls’ atmans. Practice of absolute celibacy for a minimum period of 12 years in continuation is also necessitated, only then we could awaken our kundalini shakti fully.
The most enlightening part of Bhagavad Gita is, the original gist of Bhagavad Gita containing 700 shlokas verses in Sanskrit with English transliteration is available for mere $1 from Gita press, Gorakhpur, India still, none world over seems interested. Reason being none seems competent to indulge in contemplation (chintan) a requisite to understanding hidden underlying meaning of sacred texts containing Bhagavad Gita.
Mastering delicate art of contemplation (chintan) is the most important requisite of spiritual travel.