Jeremy Bentham, answered from the texts and cited to the page.
Morality and law must be divorced from religion. All we can know is rooted in the senses; of the supernatural we can know nothing, and what is said of it is nonsense. Asceticism — the approval of pain and the censure of pleasure — is the one principle exactly contrary to utility, and it has no warrant even in the teaching of the hedonist Jesus; it was Paul, the impostor, who introduced it.
Religion produces misery by the fear of supernatural punishment and lends its sanction to misrule. In the matter of sex, the distinction between "regular" and "irregular" gratification is no law of nature but a social construct; consenting acts that harm no one — including those between man and man, then punishable by death — are no fit subject for the penal law. Marriage is a contract, to be entered for such term as suits the parties.12
But this is done only to try us, in order just to see how we should behave: which it is-plain he could not know, without making the experiment. Now then, from the satisfaction it gives him to see us make ourselves as unhappy as we can make ourselves in this present life, we have a sure proof of the satisfaction it will give him to see us as happy as he can make us in a life to come.An Introduction to the Principles of Morals and Legislation, p. 18
'To insert or not', and have been marked for possible deletion. 11 See Traités de législation civile et pénale, ii. 212-14.Not Paul, But Jesus Vol III, Doctrine, pp. 67–68
Much of this lay in manuscript: Bowring suppressed the religious writings, and Of Sexual Irregularities was not edited until 2014. The argument on Sodom anticipates McNeill; the argument against the prohibition of suicide anticipates Singer on euthanasia. The decriminalization of consensual acts that Bentham urged was not achieved in England for a century and a half after his death.