New International Version
Oaths 33 “Again, you have heard that it was said to the people long ago, ‘Do not break your oath, but fulfill to the Lord the vows you have made.’ 34 But I tell you, do not swear an oath at all: either by heaven, for it is God’s throne; 35 or by the earth, for it is his footstool; or by Jerusalem, for it is the city of the Great King. 36 And do not swear by your head, for you cannot make even one hair white or black. 37 All you need to say is simply ‘Yes’ or ‘No’; anything beyond this comes from the evil one.[a]
Thursday - June 9
“Thus you see that in this petition we pray just for that which God demands in the Second Commandment; namely, that His name be not taken in vain to swear, curse, lie, deceive, etc., but be usefully employed to the praise and honor of God. For whoever employs the name of God for any sort of wrong profanes and desecrates this holy name, as aforetime a church was considered desecrated when a murder or any other crime had been committed in it, or when a pyx or relic was desecrated, as being holy in themselves, yet become unholy in use. 46 Thus this point is easy and clear if only the language is understood, that to hallow is the same as in our idiom to praise, magnify, and honor both in word and deed.” (Luther’s Large Catechism, the Lord’s Prayer).