Psalms 118:106

106. “I have sworn, and am stedfastly purposed to keep Thy righteous judgments” ( ver. 106 ): as one who walked aright in the light of that lantern, and kept to straight paths. For he calleth what he hath determined by a sacrament, an oath; because the mind ought to be so fixed in keeping the righteous judgments of God, that its determination should be in the place of an oath. Now the righteous judgments of God are kept by faith; when, under the righteous judgment of God, neither any good work is believed to be fruitless, nor any sin unpunished; but, because the body of Christ hath suffered many most grievous evils for this faith, he saith, “I was humbled above measure” ( ver. 107 ). …

XXIX. It is especially desirable that attention should be given to the case of persons in power who threaten on oath to do some hurt to those under their authority. The remedy is twofold. In the first place, let them be taught not to take oaths at random: secondly, not to persist in their wicked determinations. Any one who is arrested in the design of fulfilling an oath to injure another ought to shew repentance for the rashness of his oath, and must not confirm his wickedness under the pretext of piety. Herod was none the better for fulfilling his oath, when, of course only to save himself from perjury, he became the prophet’s murderer. Swearing is absolutely forbidden, and it is only reasonable that the oath which tends to evil should be condemned. The swearer must therefore change his mind, and not persist in confirming his impiety. …

Germanus : So far as this consideration is concerned which has been clearly and fully treated of, a monk ought never to determine anything for fear lest he turn out a breaker of his word or else obstinate. And what then can we make of this saying of the Psalmist: “I have sworn and am purposed to keep Thy righteous judgments?” What is “to swear and purpose” except to keep one’s determinations fixedly?

But it, when lifted up, is forsaken, and, being forsaken, it is recalled to fear. For hence David says again, I said in mine abundance, I shall not be moved for ever ( Ps. xxix. 7 ). But he added a little later what he underwent for having been puffed up with confidence in his virtue, Thou didst turn thy face from me, and I was troubled ( Ibid. v. 8 ). As if he would say plainly, I believed myself strong in the midst of virtues, but, being forsaken, I become aware how great was my infirmity. Hence he says again, I have sworn and am stedfastly purposed to keep the judgments of thy righteousness ( Ps. cxix. 106 ). But, because it was beyond his powers to continue the keeping which he sware, straightway, being troubled, he found his weakness. Whence also he all at once betook himself to the aid of prayer, saying, I am humbled all together; quicken me, O Lord , according to Thy word ( Ibid. …