Timothy was born to a pagan father and a Jewish mother named Eunice. The fact that the mother had entered into a mixed marriage and that she had not had her son circumcised suggests that Timothy grew up in a not very believing family, although it is said that he knew the scriptures from childhood (2 Timothy 3:15). When Paul came at the beginning of the second missionary journey through Lystra – today’s village of Kilistra (Gökyurt) near Konya – he chose Timothy as his companion because he had a good testimony of the brothers in Lystra and Ikonium; he was then circumcised by Paul to avoid conflict with Jews (Acts 16:2–3).
Timothy was highly esteemed by Paul. I have no like-minded person who will take care of your affairs in such a genuine way, he writes to the Philippians (2:20)
Joachim Schäfer: Article Timothy, from the Ecumenical Dictionary of Saints – https://www.heiligenlexikon.de//BiographienT/Timotheus.htm