Except they wash their hands oft - Our word "oft" means frequently, often. The Greek wore translated oft has been rendered various ways. Some have said that it means "up to the wrist" - unless they wash their hands up to the wrist. Others have said up to the elbow." There is evidence that the Pharisees had some such foolish rule as this about washing, and it is likely that they practiced it faithfully. But the Greek Word πυγμή pugmē - means properly the "fist," and the meaning here is, "Unless they wash their hands (rubbing them) with the fist" - that is, not merely dipping the finger or hands in water as a sign of ablution, but rubbing the hands together as a ball or fist, in the usual Oriental manner when water is poured over them. Hence, the phrase comes to mean "diligently, carefully, sedulously." - Robinson, Lexicon. The idea is, unless they pay the utmost attention to it, and do it carefully and according to rule.
The tradition - What had been handed down; not what was delivered "by writing" in the law of Moses, but what had been communicated from father to son as being proper and binding.
The elders - The ancients; not the old men "then living," but those who had lived formerly.

Except they wash their hands - πυγμῃ, the hand to the wrist - Unless they wash the hand up to the wrist, eat not. Several translations are given of this word; that above is from Dr. Lightfoot, who quotes a tradition from the rabbins, stating that the hands were to be thus washed. This sort of washing was, and still continues to be, an act of religion in the eastern countries. It is particularly commanded in the Koran, Surat v. ver. 7, "O believers, when ye wish to pray, wash your faces, and your hands up to the elbows - and your feet up to the ankles." Which custom it is likely Mohammed borrowed from the Jews. The Jewish doctrine is this: "If a man neglect the washing, he shall be eradicated from this world." But instead of πυγμῃ, the fist or hand, the Codex Bezae has πυκνῃ, frequently: and several of the Itala have words of the same signification. Bathing is an indispensable prerequisite to the first meal of the day among the Hindoos; and washing the hands and the feet is equally so before the evening meal. Ward's Customs.

For the Pharisees, and all the Jews, except they wash [their] hands oft, eat not, (c) holding the tradition of the elders.
(c) Observing diligently.

For the Pharisees, and all the Jews,.... The far greater part of them; all, excepting the Sadducees; and especially the Pharisees, were very tenacious of this tradition of washing hands before eating: hence Pharisees are described as such, , "that eat their common food with cleanness" (n), i.e. of hands: these,
except they wash their hands oft, eat not; or except they wash very cautiously, with great care, diligence, and exactness, as the Syriac version suggests; and about which there are various rules given, to be observed with great strictness (o). Some render the words, "they wash their hands to the elbow"; and this is a rule with the Jews, which is closely to be abode by, that the washing of hands is to be, , "to the joint", which joins the hand and arm together (p): particularly it is observed (q), that
"washing of the hands for the eating of the offering, is unto the elbow, and for common food, to the joints of the fingers: he that eats with an ancient man, and does not wash his hands to the elbow, he may not eat with him.''
Well may it be added,
holding the tradition of the elders; nor do the Jews pretend the authority of the Scriptures as obliging them to such rules; for, they say, the command concerning washing of hands is, , "from the words of the Scribes" (r); and is , "a command of the wise men" (s). The tradition is this:
"they wash hands for common food, but for the tithe, and for the first offering, and for that which is holy, they dip them, and for the sin offering; for if the hands are defiled; the body is defiled (t).''
And this tradition of the elders, the Scribes, and Pharisees, strictly observed.
(n) Gloss in T. Bab. Chagiga, fol. 18. 2. Maimon. & Bartenora in Misn. Chagiga, c. 2. sect. 7. (o) Vid. Maimon. Hilch. Bcracot, c. 6. (p) T. Bab. Cholin, fol. 106. 1, 2. Maimon. Hilch. Beracot, c. 6. 4. Maimon. & Bartenora in Misn. Eracin, c. 5. sect. 1. Zohar in Deut. fol. 115. 2. (q) T. Hieros. Betacot, fol. 12. 1. (r) Maimon. Hilch. Mikvaot, c. 11. sect. 1. (s) Ib. Beracot, c. 6. sect. 2. (t) Misn. Chagiga, c. 2. sect. 5.

For the Pharisees . . . except they wash diligently, eat not. The duty of washing before meat is not inculcated in the law, but only in the tradition of the scribes. So rigidly did the Jews observe it, that Rabbi Akiba, being imprisoned, and having water scarcely sufficient to sustain life given him, preferred dying of thirst to eating without washing his hands.