2 Corinthians 10:15
Not boasting of things without our measure, that is, of other men’s labours; but having hope, when your faith is increased, that we shall be enlarged by you according to our rule abundantly, Not boasting of things without our measure, that is, of other men’s labours; but having hope, when your faith is increased, that we shall be enlarged by you according to our rule abundantly,
The verse belongs to Paul's account of the difficulties he faced and his defense of his course, including his decision to support himself by manual tent-making while preaching the gospel. Not boasting outside measure means staying within the limit and assignment God distributed and not claiming credit beyond an appointed field or for the labors of others or for work in another person's field already made ready to hand.
The verse expresses hope that when the faith of believers increased, Paul's work would be enlarged by them and through their support abundantly according to his rule, so he could preach the gospel in the regions beyond them. There is in it no room for self-righteousness and glorifying of self, for whoever glories must glory in the Lord, and approval comes not from commending self but from being commended by the Lord.
Not boasting beyond measure comes from a close connection with God, which gives true spiritual discernment. That connection makes a person conscious of personal weakness and deficiency and unlikeness to Christ, and produces a humble view of self, a meek and lowly heart, and a prayerful and careful walk before God. The verse condemns measuring self by self and comparing self with self in order to claim favor, demand wages equal to others, sell labor to the highest bidder, become wise above what is written, and appropriate God's means for personal use.
Such self-exalting and covetous conduct is an evil leaven of selfishness and covetousness and unbelief that surrounds the soul with double-dealing, robs the treasury like the sin of Achan, cannot give the right mold to the work or supply hard fields, and brings God's judgment rather than His presence and approval, while true enlargement comes only inside God's rule through growing faith for wider gospel work. The verse therefore calls for humble earnest work to extend the truth into nearby regions beyond an established school, including places such as Newcastle and Maitland.