Contradiction with Matthew 5:37
Nehemiah 9:38 speaks of making a binding covenant, whereas Matthew 5:37 advises simplicity, letting "your communication be, Yea, yea; Nay, nay," discouraging oaths or binding agreements.
Matthew 5:37: But let your communication be, Yea, yea; Nay, nay: for whatsoever is more than these cometh of evil.
Contradiction with James 5:12
Nehemiah 9:38 refers to making a covenant, while James 5:12 warns against making oaths, advocating instead to simply say 'yes' or 'no' to avoid judgment.
James 5:12: But above all things, my brethren, swear not, neither by heaven, neither by the earth, neither by any other oath: but let your yea be yea; and [your] nay, nay; lest ye fall into condemnation.