Should anything like this happen, my labor will be lost. Indeed, the Apostle seems to express himself even more strongly: has my labor already been lost?
Have you become such that you cannot even be called Christians, but must be converted again? I fear whether matters have gone so far.
He does not say this decisively because he did not know exactly what was happening among them and with them. He did not know what to think of them (verse 20).
The Apostle does not grieve over the labor, but over them, that they may again be cast into the same darkness from which it cost him so much labor to draw them out.
Knowing that he is debtor to all, both far and near, he also grieves that the work of God is being hindered by this. He would have directed his labor to others, but here he must sweat again over the same people, who seemed already to have been set on their feet.
The reminder of his labor among the Galatians, which Saint Paul bore in converting them and establishing their churches, could produce great contrition and compunction. They had experienced the holy Apostle’s love for them and had previously shown devotion to him.
He “speaks as though saying: remember how much sweat has been poured out over you, and do not allow my labor to become vain” (Blessed Theophylact).
A vain loss is grievous. Therefore earlier he reminded them of their own loss when he said: “Did you suffer in vain?” (cf. 3:3-4). Now he speaks of the loss of his own labor.
Further on (verse 19), he writes that he is again undergoing labor, and painful labor. Practical people understand well how moving all such reminders are.
Saint Chrysostom says: “Do you see the Apostle’s sincere concern? They are storm-tossed, and he fears and trembles for them. Therefore his words, ‘I have labored among you,’ contain much that is crushing.
It is as though he said: do not make such great labors of mine vain. By the words ‘I fear’ and ‘lest perhaps,’ he awakens anxiety in them and at the same time breathes good hopes into them.
For he did not say, ‘I have labored in vain,’ but, ‘lest perhaps I have labored in vain.’ That is, this is not yet shipwreck, but I see in it a dangerous storm. Therefore I fear, but do not despair. You can still correct everything and return to your former calm.”
Blessed Jerome says the same with a particular application: “If he had wished to rebuke them decisively, he would have said, ‘I have labored in vain.’
But now, with this manner of expression, ‘lest perhaps,’ seeing that they have zeal for God, but not according to knowledge, he does not wholly despair of the salvation of those drawn into error because of immature faith, pro errore.
Yet he does not leave them without rebuke, lest he give them occasion to remain undisturbed in error, and others to fall without fear into error like theirs.
A teacher labors in vain when he strives to lead them up to what is better and higher, while they through negligence fall down into what is worse and lower.”