This Bible contradiction is from the EvilBible.com.
Taking of oaths sanctioned
Numbers 30:2 View context
If a man vow a vow unto the LORD, or swear an oath to bind his soul with a bond; he shall not break his word, he shall do according to all that proceedeth out of his mouth.
Genesis 21:23-24 View context
Now therefore swear unto me here by God that thou wilt not deal falsely with me, nor with my son, nor with my son's son: [but] according to the kindness that I have done unto thee, thou shalt do unto me, and to the land wherein thou hast sojourned.
And Abraham said, I will swear.
Genesis 21:31 View context
Wherefore he called that place Beer-sheba; because there they sware both of them.
Genesis 31:53 View context
The God of Abraham, and the God of Nahor, the God of their father, judge betwixt us. And Jacob sware by the fear of his father Isaac.
Hebrews 6:13 View context
For when God made promise to Abraham, because he could swear by no greater, he sware by himself,
Taking of oaths forbidden
Matthew 5:34 View context
But I say unto you, Swear not at all; neither by heaven; for it is God's throne: