John Lightfoot on Luke 11:38

[That he had not first washed before dinner.] Had the Pharisee himself washed before dinner, in that sense wherein washed signifies the washing of the whole body? It is hardly credible, when there was neither need, nor was it the custom, to wash the whole body before meat, but the hands only. This we have spoken largelier upon elsewhere [Matt 15; Mark 7]; from whence it will be necessary for us to repeat these things; that there is a washing of the hands, and there is a dipping of the hands. This clause we are upon refers to this latter. The Pharisee wonders that Christ had not washed his hands; nay, that he had not dipped them all over in the water when he was newly come from the people that were gathered thick together.

Of how great esteem this washing their hands before meat was amongst them, besides what I have alleged elsewhere, take this one instance more: "It is storied of R. Akibah, that he was bound in prison, and R. Joshua ministered unto him as his reader. He daily brought him water by measure. One day the keeper of the prison met him, and said unto him, 'Thou hast too much water today.' He poured out half, and gave him half. When he came to R. Akibah, he told him the whole matter. R. Akibah saith unto him, 'Give me some water to wash my hands': the other saith unto him, 'There is not enough for thee to drink; and how then shouldest thou have any to wash thine hands?' To whom he, 'What shall I do in a matter wherein there is the guilt of death? It is better I should die [that is, by thirst] than that I should transgress the mind of my colleagues'": who had thus prescribed about washing of hands.

And a little after; Samuel saith, "At that time wherein Solomon instituted the 'Erubhin' and washing of the hands, there came forth 'Bath Kol,' and said, 'My son, if thy heart be wise, even mine shall rejoice.'" Observe here, (at least if you will believe it) that Solomon was the first author of this washing of hands. "Whosoever blesseth immediately after the washing of hands, Satan doth not accuse him for that time of his repast."