Luke
Acts 16:1ESV·traditional attribution

Paul came also to Derbe and to Lystra. A disciple was there, named Timothy, the son of a Jewish woman who was a believer, but his father was a Greek.

John Calvin Reformed @genevareformer

1. Luke doth now begin to declare what were the proceedings of Paul after that Barnabas and he were separate. And first he showeth, that he took to his company at Lystra Timothy to be his companion. But, to the end we may know that Paul did nothing rashly, or without good consideration, Luke saith plainly, that Timothy was such a man as the brethren...

Matthew Henry Presbyterian @wholebiblehenry

Paul was a spiritual father, and as such a one we have him here adopting Timothy, and taking care of the education of many others who had been begotten to Christ by his ministry: and in all he appears to have been a wise and tender father. Here is, I. His taking Timothy into his acquaintance and under his tuition.

Commenting on Acts 16:1-5

Albert Barnes Presbyterian @notesbybarnes

CHAPTER 16 Verse 1. Then came he. That is, Paul, in company with Silas. Luke does not give us the history of Barnabas, but confines his narrative to the journey of Paul. To Derbe and Lystra. ". And behold a certain disciple--named Timotheus. It was to this disciple that Paul afterwards addressed the two epistles which bear his name.