Not surprisingly, the words "cross" and "to crucify" turned into a kind of taboo until, it would seem, quite recent times. For instance, the commonly used Hebrew/Aramaic dictionary to rabbinic literature compiled by Marcus Jastrow (1903) translates the relevant terms (tslb, tslybh) as "to hang, impale" and "hanging, impaling", whereas Michael Sokoloff's parallel work, published in 1990, almost always gives "crucifixion" as the appropriate meaning. If the connection between the cross and Jesus, and its anti-Semitic reverberation inspired by the popular cry, "Crucify him, crucify him", are also taken into account, it is easy to grasp why the subject was kept under cover in Jewish circles.

Nevertheless two significant references to crucifixion from outside the Mishnaic-Talmudic tradition survived in the sources. One is buried in the rarely used Targum of Ruth. Commenting on Ruth 1:17, the Aramaic interpreter lists the death penalties codified in the Mishnah-stoning, burning, beheading — but substitutes for strangling tselibat qissa, "crucifixion on the tree", thus turning the cross into a Jewish instrument of death penalty. The second source is Flavius Josephus, a non-rabbinic author, who reports that the Hasmonaean priest-king Alexander Jannaeus (103-76 BCE) crucified 800 of his political opponents. The episode could be taken, not as the outcome of due legal process, but as a horrible act of cruelty, and some Jewish historians of the last century, mistrusting Josephus, declared the anecdote unhistorical. However, the discovery of two Dead Sea Scrolls in the mid-20th century has completely changed the perspective. 

The Qumran Commentary on Nahum, officially published in 1968 in Discoveries in the Judaean Desert V by John Allegro, but released in a preliminary study already in 1956, contains according to Allegro's interpretation a reference to the death on the cross of the Teacher of Righteousness, the founder of the Dead Sea community, who in Allegro's understanding prefigured the crucified Jesus. Unanimously rejecting Allegro's interpretation, scholarly consensus maintains that the Commentary speaks in the usual figurative language of the Qumran exegesis of prophecy, of the Jewish group of the Pharisees, called "the seekers of smooth things" (teachers pretending to present the harsh truths of the Law as easy and appealing). This party is said to have invited the Seleucid (Syrian Greek) king Demetrius (named in the fragment and identified by historians as Demetrius III) to attack Jerusalem and defeat their enemy, the Jewish ruler alluded to with the sobriquet, "the furious young lion", that is, Alexander Jannaeus. The plan of the Pharisee "seekers" misfired and Jannaeus took his revenge on them and "hanged men alive on the tree". 

This metaphorical imagery neatly reflects the gruesome account of the historian Josephus, who reports that after the withdrawal of Demetrius, Jannaeus crucified 800 of his Pharisee adversaries for the crime of encouraging the Syrian king to attack Jerusalem, and made them watch from the cross the massacre of their wives and children. In legal terms, this macabre story presents crucifixion as the penalty for betraying king and country.