Straightforward again, right? As with revenge, let’s define bearing a grudge.
Revenge is when you refuse to lend someone your shovel because he had refused to lend you his hoe. Holding a grudge is when you lend it to him but you say, “I’m doing this even though you wouldn’t lend to me!” The words show that the lender in this scenario really hasn’t let go of his animosity towards the borrower. It’s time to get over it.
The reason is as we said in the previous mitzvah: when things don’t go our way, God doesn’t want us to turn on one another. Rather, He wants us to look inside ourselves. We should evaluate our own deeds and improve ourselves. (If anything, holding on to ill will only serves to drag us down further!)
This mitzvah applies to both men and women in all times and places. It is discussed in the Talmud in tractate Yoma on pages 23a and is codified in the Mishneh Torah in the sixth chapter of Hilchos Deos. This prohibition is #305 of the 365 negative mitzvos in the Rambam’s Sefer HaMitzvos and #81 of the 194 negative mitzvos that can be fulfilled today as listed in the Sefer HaMitzvos HaKatzar of the Chofetz Chaim.