Tradition
St. John Chrysostom
Homilies on First Corinthians
Homily 43 › 1 Corinthians 16:8
“But I will tarry at Ephesus until Pentecost.”
As we should expect, he tells them all exactly, informing them as friends. For this too is a mark of friendship to say the reason why he was not with them, why he delayed, and where he was staying.
Source: Homilies on First Corinthians (New Advent)