You have been told is literally “you heard.” The source of information is not mentioned; it is even possible that it was Paul himself who told them. Another possibility which has been suggested is to take “you heard” as reflecting a typical and traditional Eastern way of apologizing before mentioning one’s own experiences. This seems to be the sense implied in at least one translation (Jerusalem Bible “You must have heard”).
How I used to live translates a Greek expression referring to “manner of life,” “behavior,” “conduct.” It may be necessary in some languages to be somewhat more specific than is the English expression used to live. One may say, for example, “how I behaved,” “how I acted,” or even “what I did.”
When I was devoted to the Jewish religion translates a prepositional phrase (literally “in Judaism”). In the New Testament the word “Judaism” is used only here and in the following verse. In the deuterocanonical books of the Maccabees this term is used to refer to the Jewish religion in contrast to other religions, particularly that of the Syrian kings. It is possible that Paul is using it in the same sense here and is contrasting the Jewish set of beliefs with those of the church of God, which in this verse is how he talks about the Christian faith (compare Phillips). But some interpreters, observing that the use of the term “Judaism” in direct contrast to Christianity arose later, that is, at the close of the first century, consider it more likely that what Paul means here is adherence to the total Jewish way of life (so New English Bible and Jerusalem Bible “a practising Jew”). The clause when I was devoted to the Jewish religion may be rendered in some languages as “when I worshiped God as Jews worship God.”
With regard to this stage of his life, Paul mentions two things, although they are in reverse chronological order: (1) he was a persecutor of the church, and (2) he was an ardent student of Judaism, both in theory and practice.
Paul’s activities as a persecutor of the church are described in the early chapters of (Acts 7.58; 8.1; 9.1-2). In this verse, he admits that he persecuted the church without mercy. The Greek word contains the elements of consistency and excess, and various translations try to include either one or both of these elements (Revised Standard Version “violently,” Phillips “with fanatical zeal,” New English Bible “savagely,” New American Bible “I went to extremes,” Jerusalem Bible “merciless,” Moffatt “furiously”).
I persecuted … the church of God may be rendered as “I caused groups of believers in God to suffer very much.” In many languages it is not possible to use a collective such as the church in this type of context, but one must always use a plural form indicating various groups of believers.
The phrase persecuted without mercy may be rendered as “did everything I could to persecute,” “didn’t stop at anything in persecuting,” “strongly persecuted,” or “used violence in making people suffer.”
The imperfect tense of the Greek verb translated persecuted suggests that Paul’s persecution of the church continued for some time. The force of the imperfect tense may be expressed in some languages as “I kept on persecuting.” The imperfect tense of the verb meaning “to destroy” indicates an attempt, as well as an action which continued for a period of time; it may be rendered as “I kept on doing my best to destroy.” It is important in employing a verb for destroy to use one which would be applicable to an institution or a group of people and not merely to some building. One may sometimes use a phrase meaning “to cause to come to an end,” “to cause to cease,” or “to scatter and make disappear.”
Quoted with permission from Arichea, Daniel C. and Nida, Eugene A. A Handbook on Paul’s Letter to the Galatians. (UBS Handbook Series). New York: UBS, 1976. For this and other handbooks for translators see here .