[2:85] Then there you are killing one another, and expelling a party of you from their habitations, conspiring against them in sin and enmity, and if they come to you as captives, you ransom them; yet their expulsion was forbidden you. What, do you believe in part of the Book, and disbelieve in part?
...and if they come to you as captives, you ransom them, i.e., 'just as you protect their rights by ransoming them, so must you restrain your hands from them and forswear expelling them from their homelands. When you uphold some of what has been made obligatory for you, what keeps you from doing the rest of what you have been commanded to do? Don't you know that whoever differentiates in what he has been commanded, so that he believes in some parts and disbelieves in others has the reward for his deeds nullified because of what he has neglected?'
[2:85 cont'd] What shall be the requital of those of you who do that, but degradation in the life of this world; and on the Day of Resurrection to be returned to the most terrible of chastisement? And God is not heedless of what you do.
i.e., they thought that what they did would benefit them but it was disclosed to them in the Hereafter that everything that they did, when they mixed it with what was damaging and stripped it of sincerity and devotedness, was not accepted from them.
The captives are of different types. The rescue of the captive drowning in the sea of caprice (hawā) is being directed to guidance. The ransom of the captive who remains in the hands of whisperings (wasāwis) is to show him the way to certainty by the glimmers of proofs. Through this you will rescue him from doubt and questioning, and take him out of the darknesses of blind imitation (taqlīd). The redemption of the captive you find shackled to his random thoughts and enslaved by the clamor of his lower self is that you direct him to the witnessing of favors. [This is done] by his absolving himself of considering any power in a created thing or something other [than God]. The redemption of the captive you find tied to his error is to advise him to renounce it and to aid him in restraining himself from it. The redemption of the captive you find shackled to his [human] attributes is to direct him towards the Real in what will release him from the fetter of engendered existence (kawn). The captives you find in the grip of the Real, let them know that there is no redemption for such captives, no retaliation for their dead, and no deliverance for their bond. [For aspirants on the path] there is no escape from them, no way to them, no stratagem other than them, no comfort with anything but them, and no rejecting their decree.