We don't have free will if you believe in hell. We have an extorted choice in that case.
Free will would be to chose without consequence. I'm really surprised that many Christians don't see that. How can it be free will when if you don't chose God's way it's to hell for you?
Well, why believe in 'hell'? It's a metaphor for the longing for God denied within oneself. It's not a place, it's not a confinement, one can leave it at anytime or be in it at anytime.
Same with heaven.
So, should worship of God be from fear of punishment or hope of reward?
No.
"WORSHIP thou God in such wise that if thy worship lead thee to the fire, no alteration in thine adoration would be produced, and so likewise if thy recompense should be paradise. Thus and thus alone should be the worship which befitteth the one True God.
Shouldst thou worship Him because of fear, this would be unseemly in the sanctified Court of His presence, and could not be regarded as an act by thee dedicated to the Oneness of His Being. Or if thy gaze should be on paradise, and thou shouldst worship Him while cherishing such a hope, thou wouldst make God's creation a partner with Him, notwithstanding the fact that paradise is desired by men.
Fire and paradise both bow down and prostrate themselves before God. That which is worthy of His Essence is to worship Him for His sake, without fear of fire, or hope of paradise.
Although when true worship is offered, the worshipper is delivered from the fire, and entereth the paradise of God's good-pleasure, yet such should not be the motive of his act. However, God's favour and grace ever flow in accordance with the exigencies of His inscrutable wisdom."
(The Bab, Selections from the Writings of the Bab, p. 77)
Regards,
Scott