Here two other groups are mentioned: older women and younger women. The structure is parallel to that of verse 1 and in fact continues the idea found there. Timothy is exhorted to treat these older women as if they were his own mother, and the younger women as if they were his own sisters.

In all purity is attached at the end of the sentence and describes the way in which Timothy ought to deal with the women, particularly the younger ones. Purity is the same word used in 4.12. Here it very probably refers to being free from any immoral acts, especially acts related to sex. So other ways of expressing in all purity are “with a pure heart,” “with a heart free from immoral thoughts,” or even “not thinking or doing anything immoral toward them [the older and younger women].” In some languages it will be helpful to begin a new sentence with verse 2; for example, “You should treat (or, act toward) the older women just as if they were your own mother, and treat (or, act toward) younger women just as if they were your own sister. Do this with a pure heart.”

Quoted with permission from Arichea, Daniel C. and Hatton, Howard A. A Handbook on Paul’s First Letter to Timothy. (UBS Handbook Series). New York: UBS, 1995. For this and other handbooks for translators see here .