Ye have heard that it was said by them of old time, Thou shalt not commit adultery: but I say unto you, That whosoever looketh on a woman to lust after her hath committed adultery with her already in his heart. And if thy right eye offend thee, pluck it out, and cast it from thee: for it is profitable for thee that one of thy members should perish, and not that thy whole body should be cast into hell. And if thy right hand offend thee, cut it off, and cast it from thee: for it is profitable for thee that one of thy members should perish, and not that thy whole body should be cast into hell. It hath been said, Whosoever shall put away his wife, let him give her a writing of divorcement: but I say unto you, That whosoever shall put away his wife, saving for the cause of fornication, causeth her to commit adultery: and whosoever shall marry her that is divorced committeth adultery.
One of Rome's laymen e-apologists recently tried to argue that "if thy right hand offend thee" refers to acts associated with sexuality. I hope that my readers can discern what this layman has in mind without my spelling it out. (link, caution - discussion is more explicit there)
There are reasons not to accept this theory. For example, in a similar passage, Christ says:
Matthew 18:8 Wherefore if thy hand or thy foot offend thee, cut them off, and cast them from thee: it is better for thee to enter into life halt or maimed, rather than having two hands or two feet to be cast into everlasting fire.
It seems that Christ is simply listing important body parts.
Moreover, there is no particular reason that the use of the hand must be as this apologist suggests, but may instead refer to the act of grabbing or hailing the woman in order to act on or further the lust described.
Nevertheless, let's assume that our Roman acquaintance is on to something in Matthew 5, for the sake of the argument.
Suppose that the reference to the right hand relates to sexual desire with respect to a woman. But is it any woman? No, it is to a woman that is not one's wife. The same goes for the eye that looks on the woman.
Is there anything wrong with a man looking on his wife to desire her sexually? Surely not, notwithstanding the error of ascetics and those influenced by them. Indeed, we are taught in Scripture:
Let thy fountain be blessed: and rejoice with the wife of thy youth. Let her be as the loving hind and pleasant roe; let her breasts satisfy thee at all times; and be thou ravished always with her love.
So then it is not the sexual desire itself that is condemned, nor the looking or touching that is condemned, but the lust directed at one who is not one's wife that is condemned. But this does not fit contemporary Rome's argument on this topic. It is not a blanket condemnation of non-procreative acts, but merely a call to abstain not only from adultery in the act but also adultery in the heart.
May God preserve us from temptations to adultery in the heart and in the act!