The fact that man suffers for his bad deeds, or is rewarded for his good deeds inevitably leads to the theory of Karma.
In Sikhism, the law of Karma according to which we reap what we sow is not inexorable. The burden of our sins, the taint of Karma, the weight of all the past can be thrown off, by diving deeper into truth, by the grace of God, and by leading a purer and nobler life.
This life, the human life, is an opportunity for this freedom to rise or to fall into the pit. There is no determinism in our fate, if we rise above the level of Nature.
At the level of Nature or animal existence, we no doubt reap what we sow, but at the spiritual level of existence which can be reached by moral and spiritual efforts and illumination, man attains his freedom.
It is freedom not only from the wheel of Karma but also from birth and death. Those who lead a purely temporal life at the level of the sense, "their deeds follow them and they reap what they sow."( kirt una ka metis nah, oh apna bijia khah - Basant 1183) "But the Guru's word erases the blot of thousands of evil deeds of the past, and the greatest sinner can become the greatest
Saint." (gur ka sabad kate kot karma -1195)" Countless sins of the past life are washed away by the illumination of the Word."(kot kotantar papa kare ek ghari meh khovai- Asa 438).
It is not a mere coincidence that Guru Nanak and the subsequent Sikh Guru's had the closest doctrinal relations with the Qadariya and Chisti schools of Sufis which believed in free will in opposition to the Jabariya Sufi school of thought which according to orthodox Islam, is based on complete dependence on Divine Will.
The idea of determinism and fatalism is repugnant to the Sikh mind as it does not reconcile with the idea of reward and punishment, nor with the doctrine of Grace and Compassion.