ויתחזק ישראל. דרשו רז"ל למה צער עצמו, אמר יעקב אילו לגיון אחד שלח לנו בגדים חייבים אנו לנהוג בו כבוד ויוסף מפני שהוא בני אנהוג בו בזיון. ויתחזק ישראל, “Israel summoned his strength.” Reflecting on this exertion by Yaakov, our sages asked themselves why he subjected himself to the obvious pain of sitting up in bed? They say that Yaakov reasoned that if a mere general were to send him some clothing would he not go out of his way to show honor to such a general? How could he shame his own son by showing him less honor?