Swear not at all (cf. James 5:12). Yet, as St. Augustine points out, St. Paul took oaths in his writings (2 Corinthians 1:23; 2 Corinthians 11:31); and our Lord himself did not refuse to answer when put upon his oath (Matthew 26:63, Matthew 26:64).
He, that is to say, and St. Paul after him, accepted the fact that there are times when a solemn oath must be taken. How, then, can we explain this absolute prohibition here? In that our Lord is not here thinking at all of formal and solemn oaths, but of oaths as the outcome of impatience and exaggeration.
The thoughtlessness of fervent asseveration is often betrayed into an oath. Such an oath, or even any asseveration that passes in spirit beyond "yea, yea," "nay, nay," has its origin ἐκ τοῦ πονηροῦ; cf.
Chaucer, "Sweryng sodeynly without avysement is eek a gret synne" ('Parson's Tale,' § 'De Ira'). Martensen, however, takes the prohibition of oaths as formally unconditional and total, in accordance with the highest ideal of what man will hereafter be and require, and he sees the limitation, which he allows is to be given to these words, in the present conditions of human society.
We have an ideal duty towards God, but we have also a practical duty to those among whom we live, and the present state of human affairs permits and necessitates oaths. Hence it was that even Christ submitted to them.
Neither by heaven, etc. Our Lord further defines what he means by an oath. It does not mean only an expression in which God's Name is mentioned, but any expression appealing to any object at all, whether this be supraterrestrial, terrestrial, national, or personal.
Although God's Name is often omitted in such cases, from a feeling of reverence, its omission does not prevent the asseveration being an oath. Heaven; Revised Version, the heaven; for the thought is clearly not the immaterial transcendental heaven, the abode of bliss, but the physical heaven (cf.
Matthew 6:26, Revised Version). Heaven … footstool. Adapted from Isaiah 66:1, where it forms part of the glorious declaration that no material temple can contain God, that "the Most High dwelleth not in temples made with hands" as St.
Stephen paraphrases it (Acts 7:48). The great King is seated enthroned in the heaven, with his feet touching the earth.