God-fearing

God-fearers (Greek: φοβούμενος τον Θεόν, Phoboumenos ton Theon) or God-worshipers (Greek: θεοσέβής, Theosebes) were a numerous class of gentile sympathizers to Hellenistic Judaism, which observed certain Jewish religious rites and traditions without becoming full converts to Judaism. The concept has precedents in the proselytes of the Hebrew Bible.

Over the last 50 years a growing number of scholars of Judaic studies and history of Judaism became interested in the subject of God-fearers and their relationship with Hellenistic Judaism and early Christianity. According to most scholars, Jews that lived in the Greco-Roman world during the Hellenistic and Roman period probably were not involved in active missionary efforts of proselytism among Pagans, although some others disagree.

As Jews emigrated and settled in the Roman provinces of the Empire, Judaism became an appealing religion to a large number of Pagans, for many reasons; God-fearers and proselytes that underwent full conversion were Greeks or Romans, and came from all social classes: they were mostly women and freedmen (liberti), but there were also artisans, soldiers and few people of high status, like patricians and senators.

...
Wikipedia