Will a person enter Hell if they cause the death of two small kittens by closing a garden door, and what should they do to atone for that?

Kindness to cats is legislated and earns reward for its doer, as the Prophet, peace and blessings be upon him, said: "In every wet liver there is a reward." The death of the two small kittens incurs no blame upon you, because it was an unintentional error, and it does not fall under the warning mentioned concerning the woman who was tormented because of a cat she imprisoned. This is in accordance with the Almighty’s saying: "And there is no blame upon you for that in which you have erred." A Muslim is commanded to seek forgiveness, repent, and perform good deeds, even if he has not sinned.