Genèse 45:26

And they declared to him, saying, Joseph is yet alive, and is ruler over all the land of Mizraim. But his heart was divided, because he did not believe them.

‘VAYAPHAG’ HIS HEART. His heart passed away and ceased to believe; his heart took no notice of their words. The word vayaphag has the same meaning as the Mishnaic expression: “The fragrance of all spices m’phigin (escape).” Similar is the verse, Without any ‘haphugoth’ (intermission). The verse, And his scent is not ‘namar,’ is rendered in the Targum: “and his scent is not pag (passing away).” This is the language of Rashi. But it is not correct, for phugah is an expression of cessation and abolition, just as : give thyself no ‘phugath’ (respite). So also, Mine eye is poured out, and ceaseth not, without any ‘haphugoth,’ meaning “mine eye pours out tears steadily without cessation or intermission.” And so likewise, “m’phigin (their fragrance)” means that the spices scatter the fragrance and it is voided. So also, Therefore the law is ‘taphug,’ that is, voided and ceased. In this verse also, ‘vayaphag’ his heart [thus means that the beat of] his heart was suspended and his breathing ceased, for the movement of the heart ceased and he was as dead. This condition is known when joy suddenly comes upon one, and it is mentioned in the books of medicines that old or feeble persons cannot withstand the shock, for many of them faint when joy comes to them very suddenly. The heart widens and opens suddenly, and its natural heat goes out and scatters throughout the outer parts of the body, and the heart thus ceases to function because of its coolness. Thus the patriarch fell as dead. Scripture says, for he believed them not, in order to relate that he remained in that condition a great part of the day, and he lay so without movement because he did not believe them.
Concerning such fainting it is known that people shout to the fainting person and accustom him to that joyful event gradually until he accepts it with a tranquil spirit. And this is the meaning of the verse, And they told him all the words of Joseph, which he had said unto them, and when he saw the wagons [which Joseph had sent to carry him, the spirit of Jacob their father revived], for they shouted into his ears the words of Joseph and brought the wagons before him. Then did his spirit return to him, and his breathing began and he was revived. It is this which Scripture says, And the spirit of Jacob their father revived. Now Onkelos translated: “The Divine Presence, [which had departed from him when he was in mourning], again rested upon him.” Onkelos added this because the thing is true, and he expounded this interpretation from the word ruach (spirit), since Scripture does not say, “and Jacob their father revived,” [but rather, and the spirit of Jacob their father revived]. He thus explained the verse here as being analogous to these verses: The spirit of the Eternal G-d is upon me; And now the Eternal G-d hath sent me and His spirit;, 48:16. A man in whom is spirit.

וכי הוא מושל, do not be afraid to come to him.

ויפג לבו, his heart missed a beat, as he did not believe them. The meaning of the word is similar to Lamentations 2,18 אל תתני פוגת לך, “give yourself no respite.” [respite means stopping in that context. Ed.] The words וריחו לא נמר in Jeremiah 48,11 have also been translated as ”his bouquet has remained unspoiled,” [i.e. has never been disturbed, has remained inert, stationary. Ed.]

ויפג לבות, he passed out. His heart stopped beating briefly, something common when people have a fainting spell. This occurred at the moment Joseph’s name was mentioned by the brothers.

כי לא האמין להם. so that he had no chance to believe them. Therefore, ותחי רוח יעקב, once his spirit revived he never fainted again so that he was able to believe them. It had been the sudden joy that had been the cause of his fainting. Spirit has a habit of contracting when one suffers worry, etc., whereas it expands when one experiences joy, sometimes even beyond the boundaries of one’s body so that the body faints.

וכי הוא, and in addition to this he is מושל, the first word עוד in our verse performs a dual function, also applying to the portion relating to Joseph being a ruler.

ויפג לבו, it became weak. The very mention of Joseph provoked such a reaction from Yaakov.

כי לא האמין להם, he did not believe them as he could not fathom why they would make such a statement. Presumably, the brothers rushed in with the information, not having shown Yaakov any supporting evidence yet, such as the ten donkeys’ loads of food, the carriages etc. Once when the brothers elaborated and showed Yaakov what they had brought with them from Egypt, especially the carriages, he did believe them.