Berakhot 099

6:
In his great halakhic code Mishneh Torah Rambam lists five absolute prerequisites for reciting the Amidah, the absence of which would prevent the worshippers from performing their duty: being physically clean, being decently dressed, being in a physically clean environment, having no distracting physical considerations, and concentration [Mishneh Torah, Hilkhot Tefillah 4:1]. We must now consider each of these.

1. The worshipper must be in a state of minimal hygiene. This is assured my one's morning ablutions, which are a halakhic requirement. Upon waking in the morning one is required to ritually wash one's hands by pouring a liberal amount of water three times over each hand. Subsequently one should wash one's face. (Rambam adds that one should also wash one's feet! Rabbi Abraham ben-David of Poquières comments that he has never heard of this last requirement. Such are the differences between one rabbi living in the Middle East and another in southern France at almost the same time.) Later poskim [decisors] have also added hygiene of the mouth. After having performed these minimal courtesies to our bodies we only have to wash our hands again before worship (throughout the day) if we know that our hands may no longer be presumed to be ritually clean.
2. A second prerequisite is being decently dressed. Under normal circumstances this means being dressed in such a way that local social mores would permit your being presented to the head of state. Under unusual circumstances this requirement only precludes absolute nudity: i.e. requires minimal covering of the body at the very least. The halakhic description of this last item may be literally translated as "the heart should not 'see' the genitalia". Modern elasticated underwear meets this requirement more than adequately, but that consideration does not prevent Ĥasidim (and others) from still putting around their waists a special black 'gartel' [belt, girdle] before worship.
3. Not only our own bodies must be clean and decently covered, but another prerequisite is that the place where we recite the Amidah also be clean and decent. Most synagogues meet this requirement! However, when praying at home one should make certain that the immediate surroundings are reasonably tidy and, in particular, do not contain human bodily effluences. When there are babies around this becomes a particular consideration. Furthermore, when taking babies to synagogue, we should ensure that when they do there "what comes naturally" to them, that the covering over that part of their bodies is such that neither sight nor smell will prevent others from reciting their Amidah under the terms of this prerequisite. Modern infantware is usually more than adequate in this regard, but if it does not meet the challenge posed by a particular infant, it is a religious sensibility for the parent to remove the problem from the synagogue!
4. There are other distracting physical considerations that the would-be worshipper should take into consideration. His or her own state of external hygiene is not the only consideration: the imminent or pressing needs of internal personal hygiene must also be considered. Someone who feels an urgent and present need to evacuate either bowel or bladder should not commence reciting the Amidah ("and if they [nevertheless] do so their worship is an atrocity" [Rambam, Hilkhot Tefillah 4:10]). Involuntary yawning, hiccupping and even sneezing (!) are considered untoward under the circumstances [ibid 4:11] – as I suppose they would have been when standing before an earthly potentate possessed of absolute powers of life and death over all. However, nowadays, when we expect those invested with temporal power also to invest themselves with a modicum of tolerance and understanding, we can also confidently expect that the Power that made our bodies and their various modes of functioning will also exhibit tolerance and understanding of such minor infractions of good manners over which we have little or no control!

To be continued.