Timothy was young, yet from his youth he knew the Holy Scriptures, which made him wise in matters pertaining to salvation; see 2 Tim 3:16.
No less did his mother, Eunice, and his grandmother, Lois, guide him toward salvation. As Jewish women, they zealously instructed him in holy life. But his father was a Greek, a Gentile.
Although marriages of this sort were then very common, the situation here was not entirely favorable for an outstanding young Christian. Therefore the apostle resolved in his heart to take Timothy with him, confidently hoping that he would also be useful as a preacher.
Yet he did not hasten in this, but gathered from the believers the necessary testimony concerning him.
“We may think,” says D. Glagolev, “that the Apostle Paul found the Church of Derbe in good condition. As a result of his present visit, it was bound to improve still further.
“The coming of the Apostle Paul to Lystra was hardly such a surprise as it was in Derbe. Here there were many disciples whom Paul had gained during his first journey.
“Among them, now surely awaiting his arrival with impatience, was the well-known Timothy. From this time he became the inseparable companion and fellow laborer of the Apostle Paul.
“Paul later said of him that, as a son serves a father, so he served with him in the Gospel”; see Phil 2:20, 22.
More detailed information about Timothy is set forth by D. Glagolev, and also in my preface to the explanation of the Epistles to Timothy.