Be enlarged by you - according to our rule abundantly (ἐν ὑμῖν μεγαλυνθῆναι - εἰς περισσείαν)
Paul means that, as the faith of the Corinthians increases, he hopes that his apostolic efficiency will increase, so that Corinth shall become the basis of larger efforts, extending into other regions. The verb μεγαλύνω also means to praise or celebrate, as Luk 1:46; Act 5:13; Act 10:46, and is so explained by some interpreters here. But this would be inconsistent with the figure, to which Paul adheres. “He who can work far off is a man of great stature, who, without overstretching himself, reaches afar” (Meyer).
According to our rule
His wider labors will still be regulated by God's measuring-line.