Matthew Poole and continuators on Numbers 5:18

18 And the priest shall set the woman before the LORD , and uncover the womans head , and put the offering of memorial in her hands which is the jealousie-offering: and the priest shall have in his hand the bitter water that causeth the curse .

Before the Tabernacle with her face towards the Ark.

Partly that she might be made sensible how manifest she and all her ways were to God, and that she might be more visible to the congregation, that her shame might be greater if she were guilty; partly in token of her sorrow either for her sin, or at least for any cause of suspicion which she had given; partly as a sign that she was after a sort deprived of the help and protection of her husband, which the covering of the womans head signified, 1 Cor. 11. 5, 6, 7, 10. and that she was neither virgin nor loyal wife, for the heads of both these used to be covered.

That she her self might offer it, and therefore call God to be witness of her innocency.

So called either from the bitter rast which the dust gave it. or from the bitter effects of it upon her, if she were guilty. Compare Exod. 32. 20.

Not by any natural power, but by a supernatural efficacy ordained and wrought by God for her punishment, and for the terrour and caution of others.