Do not swear falsely over the denial of a monetary matter.
“Do not lie to one another” Vayikra 19:11
If someone sues his friend regarding a monetary claim worth a small coin and above, where if he admitted to it he would be obligated to pay but instead denied it and took an oath, or the plaintiff said an oath regarding the defendant and he falsely denied it.
The defendant is punishable even if he did not answer amen.
This is an oath over a pikadon/ object entrusted for safekeeping, he must pay the principal sum and a fifth.
Whoever violates this prohibition also violates “do not swear falsely by My name” Vayikra 19:12 which applies to an oath of expression. (-31)
If a person denies his friends claim to real estate or deeds and swears falsely, although he is free of penalty regarding the oath of pikadon/ object entrusted for safekeeping, he is nevertheless liable on account of the oath of expression, since he swore to a lie.
This applies in all places at all times for men and women.