In Radhanath Swami’s excellent book The Journey Home – Autobiography of an American Swami there is a nice quote from Srila Prabhupada about the difference between the personal and impersonal God:
One afternoon, a guest asked Srila Prabhupada this very question. “Is God formless and impersonal or does He have form and personality?” The chattering of birds, screeching of monkeys, and honking of distant rickshaw horns were silenced by the anticipation in my heart. I sat up with attention, eager to hear his answer.
Srila Prabhupada slowly leaned forward, his face perfectly relaxed and full lips curved downward at the edges. Sitting cross legged on the floor, his elbows rested on the low table in front of him and his hands were clasped together under his chin.
With a grave gaze, he quoted from the Vedas and explained, “We must first understand the inconceivable nature of God. The Supreme Lord is simultaneously personal and impersonal. It is an eternal truth that He is both formless and that he has an eternal, blissful form.”
I felt a warm, peaceful sensation flood my chest. With one hand Srila Prabhupada stretched his index finger upward. “The Lord’s impersonal, all pervading energy is called Brahman. And Bhagavan is the personal form of God, who is the energetic source and never under the influence of illusion.
“Take for example the sun. The form of the sun as a planet and the formless sunlight can never be separated, as they exist simultaneously. They are different aspects of the sun. Similarly, there are two different schools of transcendentalists who focus on different aspects of the one truth.
“The impersonalists strive to attain liberation in the Lord’s impersonal formless light, while the personalists strive for eternal loving service to the Lord’s all attractive form. There is no contradiction.
“Similarly, the soul is part and parcel of the Lord, simultaneously one with God and different from God. Qualitatively we are one with God, being eternal, full of knowledge, and full of bliss. But quantitatively, we are always but a part, just as the sunray is but a tiny part of the sun and yet has the same qualities as the sun.
“We are both one with God and different from God. God is the independent controller, but when the soul misuses his God given independence, he forgets his relation to the Lord and falls into illusion and subsequent suffering.”
Leaning back against the wall, he tilted his head slightly and gazed directly into my eyes. “The two schools, personalists and impersonalists, both approach different aspects of the One God.”
He went on to explain how Krishna, His form, qualities, personality, and abode were unlimited, and that all the true religions of the world worshipped the same One God. He had simply revealed Himself in different ways at different times.