In the Sermon on the Mount, Jesus cautions concerning the allure of worldly wealth. His views resemble the shunning of excessive riches by the Pharisaic Hasidim (Pious Ones) and the Essene community from Qumran. Couched within Jesus’ teaching is an idiom which is difficult to translate, “If your eye is single, your whole body is full of light” (Matt. 6:22). The Hebraic expression, “good eye” to denote generosity is well known in the Bible (Deut. 15:9; Prov. 22:9; 23:6; 28:22; Eccl. 14:10) and the writings of Israel’s Sages (m. Avot 5:15). Nevertheless, in Matthew 6, where you would expect to find the idiom, “good eye,” the adjective used in our saying is not καλός (kalos, good, pleasant) but ἁπλοῦς (haplous, single, simple).
The sense given to the enigmatic phrase by scholars to read “good eye” corresponds with the phrase in the following verse, “If your eye [is] evil” (i.e., greedy). Nevertheless, we are still confronted with the problem that the Greek wording in our verse does not read “good eye” but “single eye.” Unfortunately, nothing in known Hebrew literature is sufficiently close to our saying to present a direct parallel. Instead, we need to look at the surrounding Gospel context, as well as at similar notions found in the spiritual environment of first-century Judaism.