Adam Clarke on Acts 16:2

Which was well reported of - These words are spoken of Timothy, and not of his father. At this time Timothy must have been very young; for, several years after, when appointed to superintend the Church at Crete, he appears to have been then so young that there was a danger of its operating to the prejudice of his ministry: 1Tim 4:12, Let no man despise thy youth. He had a very early religious education from his godly mother Eunice, and his not less pious grandmother Lois; and, from his religious instructions, was well prepared for the work to which God now called him.