‘But I hope that you will know that we are not reprobate (failing the test).'
And his hope is that as they do this they will come to recognise that Paul and his fellow-workers are not reprobate, not God-rejected, because they will recognise in them both the manifestation of Christ's weakness, (through their sufferings) and of His power (through their effectiveness). Thus will they be saved from what God might do among them as he reveals His power in judgment.