For the Sake of the Jewish People

As told by 
Eliezer Zalmanov, 
who heard it from 
Reb Chaim Klein

The Righteousness of Leah

The Torah tells us how Lavan fooled Yaakov and brought Leah to the canopy instead of Rochel. At that point, we read this verse:
ויהי בבקר והנא היא לאה
"And it was morning, and, behold, she is Leah."

However, the spelling for the word “היא” in the Torah scroll is actually the spelling for the masculine pronoun “הוא”  (meaning "he", not "she"). If we are talking about a female, Leah, why is the word written in the masculine form?

I heard a wonderful answer. When Yaakov awoke in the morning and saw Leah in his tent instead of Rochel, he raised his voice and said, “Liar, daughter of a liar, how can you do something like this?! You knew I specifically wanted to marry Rochel!”

Leah answered Yaakov, “Are you a like a tallis that is full of techeiles? (i.e., Are you perfect yourself?) You also told an untruth. When you came to get the blessings from Yitzchok, your father, he asked you, ‘Who are you?’ and you answered you were Eisav!”

Leah continued, “However, you did this because you wanted to merit the blessings of your father on behalf of the Jewish People and that was the only way to do it. You were ready for self-sacrifice on their behalf.

“So too myself. I wanted to connect myself to the Tzaddik who will and merit to build the Jewish Nation [that therefore will carry his namesake]. I had no other choice but to go on this path to achieve this merit.”

Then Yaakov realized he was just like Leah –
“והנא הוא לאה”
"and, behold, he is [as] Leah."
They both had self-sacrifice for the Jewish People.