This is a translation into English of the actual decree of Expulsion.

Sepharadim Leave Spain and Portugal Expelled by Alhambra Decree

The Kings Ferdinand and Isabella, by the grace of God, King and Queen of Castile, Leon, Aragon and other dominions of the crown - to the prince Juan, to dukes, marquees, counts, the holy orders, priors, knight commanders, lords of the castles, cavaliers, and to all Jews, men and women of whatever age, and to anyone else this letter may concern - that health and grace be unto them.
It is well known that in our dominion, there are certain bad Christians that became 'Judaized' and committed apostasy against our Holy Catholic faith, much of it the cause of interactions between Jews and Christians. Therefore, in the year 1480, we ordered that the Jews be separated from the cities and towns in our domains and that they be given separate sectors, hoping that with such separation the situation would be remedied, and we ordered that the Inquisition be established in such domains; and at the end of twelve years it has worked and the Inquisition has found many guilty persons. Furthermore we are informed by the Inquisition and others of the great harm that persists to the Christians as they interact with the Jews, and in turn these Jews try by all manners to subvert our Holy Catholic faith and are trying to prevent faithful Christians to grow close to their beliefs.
These Jews have instructed these Christians in the ceremonies and observances of their laws, circumcising their children, and giving them books with which to pray, and declaring unto them the days of fasting, and meeting with them to teach them the histories of their laws, notifying them when to expect the celebration of Passover and how to observe it, giving them the unleavened bread and ceremonially prepared meats, and instructing them in things from which they must abstain, both with regard to food items and other things requiring observance of the laws of Moses, making them fully understand that there is no other law or truth outside of this. And this is made clear based on the confessions from such Jews as well as those perverted by them that it has resulted in great damage and detriment of our Holy Catholic faith.
And since we knew the true remedy of such damages and difficulties lay in the interfering of all communications between the said Jews and the Christians and sending them forth from all our dominions, we sought to content ourselves with ordering the said Jews from all the cities and villages and places of Andalusia where it appeared that they had done the most damage, and believing that this would suffice so that those and other cities and villages and places in our reigns and holdings would be effective and would cease to commit the aforesaid. And because we have been informed that neither this, neither is the case nor the justices done for some of the said Jews found very culpable in the said crimes and transgressions against our Holy Catholic faith have been a complete remedy to obviate and to correct such opprobrium and offense. And to the Christian faith and religion it appears every day that the said Jews increase in continuing their evil and harmful purposes wherever they reside and converse; and because there is no place left whereby to more offend our holy faith, as much as those which God has protected to this day as in those already affected, it is left for this Holy Mother Church to mend and reduce the matter to its previous state, due to the frailty of the human being, it could occur that we could succumb to the diabolical temptation that continually combats us, therefore, if this be the principal cause, the said Jews if not converted must be expelled from the kingdom.
Because when a grave and detestable crime is committed by some members of a given group it is reasonable that the group be dissolved or annihilated, and the minors by the majors will be punished one by the other; and those who permit the good and honest in the cities and the villages, and by their contact may harm others, must be expelled from the group of peoples, and despite minor reasons, will be harmful to the Republic, and all the more so for the majority of these crimes, would be dangerous and contagious. Therefore, the Council of eminent men and cavaliers of our reign and of other persons of knowledge and conscience of our Supreme Council, and after much deliberation, it is agreed and resolved that all Jews and Jewesses be ordered to leave our kingdoms and that they not be allowed to ever return.
We further order in this edict that all Jews and Jewesses of whatever age that reside in our domain and territories leave with their sons and daughters, servants and relatives large or small, of all ages, by the end of July of this year, and that they dare not return to our lands and that they do not take a step across, such that if any Jew who does not accept this edict is found in our kingdom and domains or returns will be sentenced to death and confiscation of all their belongings.
We further order that no person in our kingdom, notwithstanding social status, including nobles, that hide or keep or defend any Jew or Jewess, be it publicly or secretly, from the end of July and following months, in their homes or elsewhere in our reign, risking as punishment loss of all their fiefs and fortresses, privileges and hereditary rights.
So be it that the Jews may dispose of their households and belongings in the given time period, for the present we provide our compromise of protection and security so that by the end of the month of July they may sell and exchange their belongings and furniture and any other item, and dispose of them freely per their assessment, that during said time no one is to do them harm or injury or injustice to their persons or to their goods, which would be unjustified, and those who would transgress this shall incur the punishment that befalls those who violate our royal security.We grant and give permission to the above mentioned Jews and Jewesses to take with them and out of our reigns their goods and belongings, by sea or by land, excepting gold and silver or minted money or any other item prohibited by the laws of the kingdom.
Therefore, we order all councils, magistrates, cavaliers, shield-bearers, officials, good men of the city of Burgos and of other cities and villages of our kingdom and dominions, and all our vassals and subjects, that they observe and comply with this letter and all that is contained in it, and that they give all the type of help and favor necessary for its execution, subject to punishment by our sovereign grace and by confiscation of all their goods and offices for our royal house. And so that this may come to the notice of all, and that no one may pretend ignorance, we order that this edict be proclaimed in all the plazas and meeting places of all cities and in the major cities and villages of the diocese, that it be done by the town crier in the presence of the public scribe, and that no one nor anybody do the contrary of what has been defined, subject to the punishment by our sovereign grace and annulation of their offices and confiscation of their goods to whosoever does the contrary.
And we order that it be evidenced and proven to the court with signed testimony specifying the manner in which the edict has been carried out.Given in this city of Granada the thirty first day of March in the year of our Lord Jesus Christ 1492.

Signed, I, the King, I the Queen, and Juan de Coloma, Secretary of the King and Queen who has written it by order of our Majesties.