Yosef kept his identity hidden from his brothers for a long time, requiring a lot of resilience and fortitude on his part. These emotions are expressed in two ways in the text: crying and self-restraint (va-yitapak). A close reading of the text teaches that there is an ongoing process moving from crying to crying and restraint, and finally onto a forging of restraint that is expressed through crying. Why does Yosef expose his identity in our parashah and stop restraining himself?
It is often explained that Yosef revealed the brothers passed the tests of loyalty that Yosef put before them, indicating self-change, and leading to his revealing of his identity. I would like to suggest that it is actually an ongoing disappointment that urges Yosef to expose his identity. The tests of time and Yosef’s trickery toward his brothers do not actually reveal a change in his brothers. Yosef reveals his true identity due to his recognition that his disappointment will not be resolved behind a partial and fabricated identity. I will review the different points in the Yosef story where disappointment, crying, and holding back (va-yitapak) eventually bring us to the pivotal moment of the meeting that takes place in our parashah.
Yosef’s first bout of tears happens during his brother’s first visit to Egypt. There Yosef appears to be a hardened and difficult man:
When Yosef saw his brothers, he recognized them; but he acted like a stranger toward them and spoke harshly to them. He asked them, “Where do you come from?” And they said, “From the land of Canaan, to procure food.” For though Yosef recognized his brothers, they did not recognize him… Yosef said to them, “You are spies, you have come to see the land in its nakedness.”
In light of his pseudo-suppositions of his brothers, Yosef commands that they be imprisoned in Egypt while one of them goes back home to retrieve Binyamin. After a few days, Yosef changes his mind and imprisons only one of the brothers, Shimon, while the others go home with the express demand that they not return without Binyamin.
The conversation that the brothers have at this dramatic moment forms the backdrop for the first time that we see Yosef cry:
They said to one another, “Alas, we are being punished on account of our brother, because we looked on at his anguish, yet paid no heed as he pleaded with us. That is why this distress has come upon us.” Then Reuven spoke up and said to them, “Did I not tell you, ‘Do no wrong to the boy’? But you paid no heed. Now comes the reckoning for his blood.” They did not know that Yosef understood, for there was an interpreter between him and them. He turned away from them and wept. …” (vv. 21-24)
At first glance it seems that here Yosef’s tears were triggered by the brothers’ saying: “Alas, we are at fault” regarding their behavior towards him, as a moment where they take responsibility for what happened to him.  However, the crying actually does not come directly after this statement, but rather after the remark that Reuven makes, a remark of blame, accusation, and rebuke with no remorse or taking of responsibility: “Did I not tell you..!?” Yosef’s tears come specifically at this moment, when he is disappointed in his brothers for not taking responsibility for their actions.
In this scene, no holding back (va-yitapak) is described. It seems that Yosef is not moved to reveal his identity in this encounter with his brothers.
The second time that Yosef cries is the second time that he encounters his brothers, this time with Binyamin. At this juncture we see him try to restrain himself, va-yitapak:
Looking about, he saw his brother Binyamin, his mother’s son, and asked, “Is this your youngest brother of whom you spoke to me?”… With that, Yosef hurried out, for he was overcome with mercy toward his brother and was on the verge of tears; he went into a room and wept there. Then he washed his face, reappeared, and controlled himself (va-yitapak)…”
Yosef is flooded with feelings of mercy and compassion toward his brother, toward Binyamin. It seems that Yosef does not trust his brothers and so when he sees his brother “the son of his mother” he dreads that his brothers, the sons of his father, will treat Binyamin the way they treated him and is filled with mercy toward him. 
There is a short teaching found in the Pesikta Zutrata (11-12th century work of midrash) that explores the connection between overflowing emotions and crying:
“He wanted to cry.” This teaches that crying extinguishes the burning coals of the heart.
Yosef succeeds in this second bout of crying to hold himself back, va–yitapak. It is possible that the tears indeed quench his overflowing emotions, and further, it seems that the compassion he feels toward Binyamin is not sufficient motivation to bring him to reveal himself. But, in the third scene of Yosef’s crying, the one that appears in this week’s parashah, the crying is preceded by an inability to hold back, “and Joseph could no longer control himself” (45:1). Why does Yosef lose his restraint here?
The backdrop to Yosef’s stopping to hold back is a speech that Yehudah gives. What is it about Yehudah’s speech that eviscerates Yosef’s ability to control himself? It is often seen in Yehuda’s speech a revealing of the fact that Yehudah withstood Yosef’s tests. It would seem that Yehudah takes responsibility for Binyamin, Rachel’s son. This is apparent toward the end of his speech where Yehudah explains to Yosef:
“Now your servant has pledged himself for the boy to my father, saying, ‘If I do not bring him back to you, I shall stand guilty before my father forever.’ Therefore, please let your servant remain as a slave to my lord instead of the boy, and let the boy go back with his brothers. For how can I go back to my father unless the boy is with me? Let me not be witness to the woe that would overtake my father!”
But actually in these words Yehudah does not express loyalty toward Binyamin as his brother but rather a fear of not keeping the promise he made toward his father. Thus Yosef once more finds himself disappointed with his brothers. This appears to be the impetus for revealing his identity.
A law from the Rambam’s Laws of Repentance enhances this understanding according to which Yehudah’s words do not indicate change. As a result, Yosef understands that there is no chance, no remorse, and thus no forgiveness, without his sharing of his true full identity.
All the mitzvot in the Torah… if a person transgresses one of them… when they repent and return from their sin, they must confess… What is complete repentance? This is one who has the ability do something that they have transgressed in [before] and it is possible for them to do it [again], but they separate themselves and do not do it.
Full teshuvah, full penitence is possible only when circumstances are duplicated. This is possibly not only true from the point of view of the sinner, but also from that of the one being sinned against.
Let us return to Yosef: A duplication of circumstances, atonement, and forgiveness none of them are possible as long as Yosef does not take the risk of sharing his true identity. Yosef’s absence from Yehudah’s words is alarming. Moreover, throughout his speech Yehudah praises Yosef again and again. It would seem that being praised by a brother that was so alienated in the past would make Yosef feel moved to lack of restraint and tears. But the praise is stated by Yehudah when he does not recognise truly the addressee of his praise, he is not aware of his connection to him-as Yosef his brother. The words “your servant” and “master” are repeated again and again in Yehudah’s speech and every utterance of them distances Yehudah from Yosef even more:
Then Yehudah went up to him and said, “Please, my lord, let your servant appeal to my lord, and do not be impatient with your servant, you who are the equal of Pharaoh. My lord asked his servants, ‘Have you a father or another brother?'”…
Yehudah is approaching the leader in Egypt and not his brother whom he sold.
It seems that Yosef is heartbroken and can no longer restrain himself because he, “Yosef” is completely missing from Yehudah’s words. It is this alienated speech that clarifies to Yosef that his ongoing disappointment will not cease as long as he does not reveal his identity to his brothers. It is true that there is no guarantee that fraternity will emerge from this revelation, but there is no chance for repair and connection as long as the nature of the rift remains hidden.
“Yehudah approached him… and Yosef could not hold himself back.” As long as Yehudah continues to approach the ruler of Egypt rather than Yosef his brother, Yosef will remain disappointed and unsatisfied. That is why Yosef can no longer va-yitapak, no longer restrain himself.
Yosef teaches us that relationships require exposure. As long as we maintain our covers and masks, our relationships remain unsatisfying. An act of exposure requires courage, a courage which is necessary in order for relationships to become fulfilling and to bring us peace of mind.
May we merit the strength for self-disclosure and the fruit of the relationships that come in its wake.
 And perhaps it was their entire statement: “Alas, we are being punished on account of our brother, because we looked on at his anguish, yet paid no heed as he pleaded with us” that brings Yosef back to the painful moments of fear and uncertainty before being sold by his brothers that bring tears to his eyes.
 Some commentators understand these tears as tears of relief.