Biography
Rabbi Pinchas ben Yair was a tanna active around 200 CE in Lod (Lydda), in Roman Palestine, and is traditionally buried in the old cemetery of Safed. He is best known in the cited literature for a celebrated teaching — quoted in Orchot Tzadikim and made the structural backbone of Ramchal‘s Mesillat Yesharim — laying out a graded ladder of spiritual ascent: Torah leads to carefulness (zehirut), carefulness to alacrity (zerizut), and onward through cleanliness, purity, separateness, and holiness, ultimately to the resurrection of the dead. Ramchal repeatedly returns to this baraita, treating its ordering of the stages of piety as the framework for the entire ethical work.
Sources & notes. Dates, place of activity, and burial per Wikidata.
Where traditions differ. Many cited passages name 'Rabbi Pinchas bar Chama' / 'Rabbi Pinchas the Kohen ben Chama' or simply 'Rabbi Pinchas' — these appear to be a different sage (an Amora) and were not attributed to Pinchas ben Yair in this biography.
רבי פינחס בן יאיר היה תנא בן הדור החמישי לתנאים.
Pinchas ben Yair was a Tanna of the 4th generation who lived, probably at Lod, in the late 2nd century. He was the father-in-law of Shimon bar Yochai and a fellow disciple of Judah haNasi. He was more celebrated for piety than for learning, although his discussions with his son-in-law demonstrate great sagacity and a profound knowledge of tradition.
On Wikipedia: עברית · English — summary from Wikipedia, CC BY-SA