Numbers 5:6

Acting treacherously against Adonoy. Scripture now reiterates the parshah of the thief who swears falsely, previously stated in the Portion of Vayikra, “[If a person sins] . . . and acts treacherously against God, lying to his fellow . . .” It is repeated here for the sake of two innovations. Firstly, Scripture writes “And they confess . . . [their sin],” teaching that he (the thief) is not required to pay the fifth and bring the asham (guilt-offering) when convicted by the testimony of witnesses, unless he confesses to the act. And secondly, [to teach] that property stolen from a proselyte must be given to the kohanim.

Say to the children of Israel: A man or a woman who committeth any human sin, in acting perversely before the Lord, and hath become guilty;

WHEN A MAN OR WOMAN SHALL DO ANY OF THE SINS OF MAN. [The sense of the verse] is as follows: “If a man does any of the sins by which one can transgress, of any sin which man commits against another man, and he deals falsely with his neighbor [—that soul shall be guilty].” He states [here] to commit a trespass against the Eternal, which means that he swears by His Name falsely and is thus guilty before Him [as well]. Now because this sin has already been mentioned, and here it only comes to introduce the new point concerning robbing a proselyte, He deals with it briefly. He stated here a man or woman because since it is not usual for a woman to rob, [we might think that] perhaps Scripture does not make her liable to pay the additional fifth or to bring a guilt-offering [when she confesses the sin], Verse 25. like a man, [therefore He stated here a man or woman, teaching that her liability is in all respects the same as that of a man]. He mentioned [here], And every heave-offering of all the holy things of the children of Israel, which they present unto the priest, shall be his, meaning to say that once they have given the heave-offering to the priest it becomes his [personal property], and he who robs it from him is to be dealt with in accordance with the law of the guilt-offering for robberies. That is the reason why He mentioned it here. Or it may be that [this verse] comes to complete the laws of the priests regarding the heave-offering, since till now He only mentioned them by way of allusion, [stating] Thou shalt not delay to offer of the fulness of thy harvest, and of the outflow of thy presses,, (Vol. II, pp. 398-400). and so also, they may eat of his bread, but He did not explain the law of the heave-offering at all, that it is to be given to the priest; and as for the tithe, He [only] mentioned at the end of Torath Kohanim [i.e., the Book of Leviticus] that it is holy unto the Eternal., 27:30. Now, therefore, He came to command that the heave-offering and the holy gifts should belong to the priests by the grant of the owners, who may give them to them as they please, meaning to say that the benefit of satisfaction [of choosing to whom to give it] belongs to the owner [and the priest may not come and take it by force, since the owner may have the pleasure of giving it to any priest he chooses].
The meal-offering of the sotah is a woman suspected of adultery, and is …

חטאת האדם, This is also because of גזל הגר, robbery from a convert who left no children after death and to whom no restitution can be made, nor to any of his non existent heirs. This is the reason why this has been repeated here.

'למעול מעל בה, our traditional sources already told us that the subject is robbery from a proselyte who dies intestate before the robber confessed and made restitution. The robber had committed an act of desecrating the name of G’d in the eyes of the proselyte who must be appalled that a natural born Jew could be guilty of such a deed. This is why the sin of the robber in this verse is described as a “transgression against something sacred.”