Because Paul’s travels brought him into contact with many people, and some of them repeatedly, it is particularly instructive to compare the notices of some of those people in the book of Acts with the references and allusions to them in Paul’s own letters. Of those people, few are more interesting than Timothy.
In 1 Corinthians 4:17, Paul explains that he has sent Timothy, “my beloved and faithful child in the Lord, to remind you of my ways in Christ …” From that passage alone, however, we cannot tell whether he has sent him before the letter or with it, in which case the language of “sending” would be anticipation of the act. The language of 1 Corinthians 16:10-11 makes it plain that Paul had sent Timothy before writing the letter, as he speaks of Timothy’s arrival as something independent from their receipt of the letter itself – “If [or when] Timothy comes, …”
But the comparison of these two passages raises an interesting question. If Timothy had been sent first, why should he not arrive first? And if he arrived first, what use would it be to send, after the fact, instructions on how they were to receive him?
The only plausible resolution is that Timothy, though sent first, must have taken some indirect route to Corinth. The fastest method of travel from Ephesus, where Paul was writing, to Corinth would be to take a ship; with a fair wind, the journey between these two cities on opposite sides of the archipelago can be made in a very short time. But turning to Acts 19:21-22, we discover that Timothy, when he left Ephesus, took the land route, and went up through Macedonia.
Here once again we have the characteristic of undesigned coincidences that neither the historical account nor the letters could plausibly be said to have been written up from the other. The letter does not mention Timothy’s journey through Macedonia at all; the book of Acts does not mention Paul’s letter. But what we find in the book of Acts is the only plausible way of reconciling those stray comments Paul makes in the letter.
It is not always so in historical work. Jortin’s Life of Erasmus, for example, is framed almost entirely from Erasmus’s letters, and for just that reason it gives us virtually nothing that cannot be found in the letters themselves. There is much parallel material between the letters and Jortin’s biography, but there is no interlocking. The coincidences do not qualify as undesigned.
Another example comes from 2 Timothy 3:15, this time a description of Timothy rather than a reference to his travels:
… and how from childhood you have been acquainted with the sacred writings, which are able to make you wise for salvation through faith in Christ Jesus.
Clearly, this is a reference to the Jewish scriptures; but Paul gives no clue as to how Timothy, who was not circumcised until after his conversion as a young man (Acts 16:3), had acquired such knowledge.
The puzzle is cleared up in Acts 16:1:
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.
Apparently Timothy’s father drew the line at circumcision. But his mother made sure he was instructed in the scriptures of her people.