Giving no occasion of stumbling in any thing (mēdemian en mēdeni didontes proskopēn). Proskopē, late word (Polybius, lxx), from proskoptō, to strike against, to stumble. Only here in N.T. Note double negative in the Greek.
That the ministry be not blamed (hina mē mōmēthēi hē diakonia). Negative purpose (hina mē). First aorist passive subjunctive of old verb mōmaomai from mōmos, blot, blemish. One can read with profit J. A. Hutton’s Warrack Lectures, That the Ministry Be Not Blamed.