By practicing all integral steps of Yoga, impurities are destroyed and spiritual illumination arises, which develops into awareness of Reality. – Patanjali. Sadhana Pada – Spiritual Disciplines
(1) Jnana Yoga is like crossing a river by swimming. Bhakti Yoga is like crossing a river by a boat.
(2) The Jnani gets knowledge by self reliance and assertion. The Bhakta gets Darshan of God by self surrender.
(3) The Jnani asserts and expands. The Bhakta dedicates and consecrates and contracts themselves to the Lord. Suppose there is one rupee in the body of a small circle. This rupee contracts and merges itself into the circumference. This is Bhakti. Imagine there is a two anna piece in the centre of a circle. This coin so expands that it occupies the whole body of the circle and the circumference also. This is Jnana.
(4) A Bhakta wants to eat sugar candy. A Jnani wants to become sugar candy itself. (5) A Bhakta is like a kitten that cries for help. A Jnani is like a baby monkey that clings itself boldly to the mother.
(6) A Bhakta gets Krama Mukti. A Jnani gets Sadyo Mukti.
(7) A Jnana Yogi exhibits Siddhis through will or Sat Sankalpa. A Bhakta gets all the divine Aisvaryas through self surrender and the consequent descent of Divine Grace.
In the Bhagavad Gita (IV-39), Lord Krishna clearly points out that Bhakti and Jnana are not incompatibles, like oil and water. He says: “Sraddhavan labhate jnanam” – The aspirant who is full of faith obtaineth wisdom.
(8) A Jnani needs the essense to Bhakti to prevent a dry heady egoistic approach to their studies.
“Tesham satatayuktanam bhajatam preetipurvakam; Dadami buddhiyogam tam yena mamupayanti te” –
To these ever harmonious, worshipping in love, I give the Yoga of discernment by which they come unto Me.” (BG X-10. )
“Bhaktya maamabhijanati yavanyaschasmi tattvatah; Tato mam tattvato jnatva visate tadanantaram”
By devotion he knoweth Me in essence, who and what I am; having thus known Me in essence, he forthwith entereth into the Supreme. (BG XVIII-55. )
To deny Jnana altogether, to say that there is nothing beyond Goloka, is the height of one’s folly. To deny Bhakti and Isvara is also foolishness. A happy combination of Jnana and Bhakti, head and heart, is perfection.
From the DLS article Bhakti and Jnana by Swami Sivananda