Contradiction with Matthew 5:33-37
Leviticus 27:1 discusses vows, whereas Matthew 5:33-37 advises against making oaths altogether, suggesting instead that one should simply say 'Yes' or 'No'.
Matthew 5:33-37: Again, ye have heard that it hath been said by them of old time, Thou shalt not forswear thyself, but shalt perform unto the Lord thine oaths:
Contradiction with Ecclesiastes 5:4-5
Leviticus 27:1 involves making vows to God, but Ecclesiastes 5:4-5 warns that it is better not to vow than to make a vow and not fulfill it, showing caution against making vows.
Ecclesiastes 5:4-5: When thou vowest a vow unto God, defer not to pay it; for [he hath] no pleasure in fools: pay that which thou hast vowed.
Contradiction with James 5:12
Leviticus 27:1 encompasses speaking vows, but James 5:12 instructs believers to avoid swearing entirely and to commit only to simple affirmations.
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.