Just as in Mitzrayim it was said of Yosef Hatzaddik, "VeYosef hu hamashbir," he was the supplier of sustenance to all, so it was said of the Beis Yosef. He is the one who supplies spiritual sustenance and guidance to every Jew, even today, from the moment he is born until his last breath.
As the Chidah cites in his sefer Shem Hagedolim, in his time there were three great personalities by the name of Yosef who had the potential to write the Shulchan Oruch. However, Rabbi Yosef Karo was chosen by Heaven to be the one to actually carry out the task, because of his extreme humility. Indeed it is known that mishnoso mishnas chassodim, his learning was carried out in a gentle manner, with never a sharp argument.
When his sefer Beis Yosef was published, a work that clarified the Tur, there was fear amongst the gedolei hador that there would be a general decline in thorough Torah learning. Up to then, the gemora had to be learnt with the Rishonim and a further investigation into the sugya in Shas had to be carried out to come to the right conclusion. However, with the Beis Yosef's detailed summary, all the yegi'ah could be skipped and the final results are already set out on a platter — literally a set table.
In fact, a godol of the time, HaRav Yosef ben Lev, forbade his talmidim to learn with the sefer of the Beis Yosef, instructing them rather to toil in the depths of the sugya themselves. His talmidim obeyed him until one day they became entangled in a difficult sugya with no one finding a way out. The difficulty was brought to their rebbi, the Rivad, but it seemed that the fountains of wisdom were closed to him too.
Seeing that no solution was forthcoming, one talmid, after much hesitation, dared to venture that perhaps they should look up the matter in the sefer of the Beis Yosef.
There they found their questions resolved so clearly that all doubts vanished.
"It seems," announced HaRav Yosef ben Lev, "that it is the desire of a Higher Authority that the sefer rise in status to be recognized and spread amongst Klal Yisroel. From now on, whoever wishes can learn from the Shulchan Oruch."
In a short time the sefer became the sefer for any learning Yid. Many leaders would cite the posuk written about Yosef Hatzaddik, "Go to Yosef, what he will tell you — do" (Bereishis 41:55) to mean that the halochoh is decided as the Beis Yosef paskens.
Rabbi Yosef Karo's peers all held him in extremely high regard. The Ramo, who wrote a commentary on the Beis Yosef, writes in his introduction that the magnitude of the Beis Yosef's greatness defies description and mere mortal words only detract from his honor. He concludes that he will therefore just ask of Hashem that the Beis Yosef's days be lengthy and pleasant.
In his sefer Sheilos Uteshuvos HaRamo, he writes, "One who disagrees with him (the Beis Yosef) is as though he disagrees with the Shechinah."
The author of Urim VeTumim states that since the days of the Amoraim Ravo and Reb Yosef there has never been one like this Reb Yosef.
In the sefer Sheilos Uteshuvos Nachlas Shiva, a letter is quoted from Rabbi Shmuel Kaidenover to the author. There he writes, "Everything you wrote to me is mistaken. Apparently the reason for your erring is that you do not have the seforim of the Beis Yosef."
Many are of the opinion that the sefer of the Beis Yosef became so widely acclaimed because he was a "musmach." The term musmach was used in the era of the Sanhedrin to refer to one who is empowered by a superior to carry out dinei Torah where malkos or other punishments were applicable. The original chain of semichoh from Moshe Rabbenu was broken at some point due to the years in golus.
However, the rov of the Beis Yosef, the Mahari Beirav, reinstated the title.
During the period following the Spanish expulsion, many Marranos — Jews who had pretended to be Catholic but secretly held onto their faith — escaped Spain for the safer shores of Eretz Yisroel. After a perilous journey they arrived in the Holy Land only to be rejected by the Yidden there. The reason was that they had transgressed commandments that are punishable by malkos, yet there was no musmach to punish them and exonerate them.
Seeing their predicament, the Mahari Beirav decided to follow the Rambam's psak: that if a godol hador gives over semichoh to his talmid, he is a true musmach who can deliver malkos.
Taking four of his talmidim, including the Beis Yosef, he ordained them as musmachim. They could now punish the Marranos, cleansing them of their sin and allowing them to be accepted into the ranks of Klal Yisroel.
This practice of ordaining a musmach was subsequently discontinued.
Undoubtedly the chapter of the life of Reb Yosef Karo that is most shrouded in mystery is that of his revelations from Heaven. Frequently a mal'ach referred to by R' Yosef as "The Maggid" would present itself to the Beis Yosef, teaching him chochmas haTorah and revealing numerous secrets.
Some of the amazing revelations were written by the Beis Yosef himself in his sefer Maggid Meishorim.
Concerning the above sefer, the Chidah writes in his sefer Sheim Hagedolim that its contents are only one fiftieth of the true revelations of the Maggid.
The Maggid reported to the Beis Yosef that in the upper spheres a voice was heard announcing that every psak of the Beis Yosef's is true. "So why were you so fearful of laying down the psak?" the mal'ach asked, and then added, "Perhaps it was this fear that gave you the zchus."
Some other messages from the angel were: "The meat they brought you today is treif." "The Rambam is happy with you, for you understood the true pshat in his words." "Know that HaKodosh Boruch Hu rejoiced with the pilpul you gave today even though you didn't reach the final truth."
Furthermore, the Maggid related to R' Yosef, "If you were given permission to see what goes on in Heaven every time you go out to the shuk you would see hundreds of mal'ochim surrounding you on all sides, escorting you on your way like the royal escort of a majestic king, and announcing, `Make way, honor the image of the Holy King.' "
In one of the sifrei Kabboloh Metzaref LeChochmah, a letter is brought from one of the gedolim of his generation, stating that the Maggid that appears to Rabbeinu is the mishna he has just learned. He writes as follows: "Every time the Beis Yosef learned his mishnayos, the Maggid would appear to him. Through the door the Maggid could be heard to say, `Sholom Aleichem Rabbi Yosef Karo. I am the mishna you just learned. I have come to teach you a deeper understanding. Hashem in Heaven is proud of you, saying, "My son Yosef's deeds are so and so." I also have seen the designated place prepared for you in Gan Eden. Chazak Ve'ematz!"