INTRODUCTION - THE NOBILIARY CHARACTER OF THE ORDER
The Sovereign Military Hospitaller Order of Malta is a Religious and Hospitaller Order of Chivalry whose particular noble  character is still maintained today. Although it is sometimes described as a Sovereign State, it is better characterized as a Sovereign persona, since it does not possess any territorial imperium.  Nonetheless, its sovereignty is recognized as such by nearly seventy states with which it exchanges mutual diplomatic relations. Other nations acknowledge it as an Entity in International Law and, as such, it was accorded the status of Observer at the United Nations in 1994.  It still enjoys the protection of the Holy See, whose confirmation of the Order in a Bull of Pope Paschal II of 1113 makes it one of the oldest Religious Orders of the Roman Catholic Church. Its nobiliary status is a fundamental aspect of its constitution without which it would have probably lost the elevated position that has enabled it to enjoy the support of Europe's Sovereigns; their protection insured its survival after the loss of Malta. The influence of the members, who are drawn from the most elevated strata of society, has also served to maintain the Order's continued independence and prestige. As a Sovereign entity it is entitled to confer, confirm or recognize titles of nobility and establish or exercise nobiliary jurisdiction.
The Knights and Dames, the vast majority of whom compose the third class  of the Order, represent an elite among the Roman Catholic laity. The advantage of being recognized as a member of that elite also imposes an obligation of service, the responsibility of privilege which may be regarded as an essential characteristic of the Order. There are those who are uncomfortable with its elitist nature and some members of the Catholic hierarchy have demonstrated their opposition. It would be naive to suppose, however, that criticisms would cease if the nobiliary requirements for admission were relinquished. Opponents of the Order may almost always be identified with those who are opposed to the existence of any Catholic honors, including the non-noble Order of the Holy Sepulcher and the Papal Orders of Saint Gregory the Great and Saint Sylvester. The Order has never disguised the fact that entry into its ranks is difficult, a special honor and that it imposes a life-time obligation of service. It is not a good conduct medal for being a devout Catholic.
Its structure is hierarchical and its head, the Grand Master, before making profession as a knight of Justice, must have been enrolled as a member of the first rank of the third class, that of Honor and Devotion. This requires stricter proof of nobility  than the third rank of the same class, that of Grace and Devotion.  Membership of the Sovereign Council and tenure of one of the great offices of the Order is limited to members of the first class  (knights of Justice); members of the second class  (knights of Obedience) may only hold one of the great offices (Grand Chancellor, Receiver of the Common Treasure or Hospitaller) by Papal dispensation. The majority of North American knights and dames are members of the fifth rank of the third class, that of Magistral Grace, so it is rare that a North American holds high office in the Grand Magistery. 
Candidates for the first and third rank of the third class must "possess the necessary requirements by birth or by clear merits towards the Church, the Order and Humanity".  Every candidate must be a practicing Catholic of good character who has shown evidence of a willingness to serve the Order's mission and has the support of his or her local Association. It is unnecessary for a candidate for the first and third ranks of the third class, the nobiliary ranks, to show any "special merit" unless he or she has been exempted from all or some of the nobiliary requirements by motu proprio of the Grand Master. Candidates for the fifth class, however, must "manifest merits towards the Church, the Order and one's (their) neighbor" in addition to the general, requirement of being practicing Catholics of good character. 
 Noble is a widely used word being both an adjective and a noun. The former may be defined as "Of, in, or belonging to the nobility; having or sharing qualities of high moral character, as courage, generosity, or honor; superior in nature or character; exalted; grand and stately in appearance; majestic", or, as a noun, "a member of the nobility". The nobility may be defined as "a class of persons distinguished by high birth or rank; aristocracy; noble rank or status; the state or quality of being noble" (American Heritage Dictionary).
 See Prof Gerald Draper, Functional Sovereign and the Sovereign Military Hospitaller Order of St. John of Jerusalem, of Malta, in the 1974 Annuale, pp. 78-83.
 By Resolution of the UN General Assembly, no 48/265, 24 August 1994.
 The second and fourth ranks of this class, of Conventual Chaplains "ad honorem" and Magistral Chaplains are limited to priests in Holy Orders.
 Although the word "nobility" was given a negative interpretation by some of the founding fathers of the United States, it is worth recording that the virtues of nobility are generally considered positive. The seventeenth century writer Benedict Spinoza, in defining nobility, for example, wrote that "temperance, sobriety and the presence of mind in danger, etc, are species of courage; but modesty, clemency, etc are species of nobility" (Ethics, 1677, pt III, proposition 59).
 In the British Association, for example, proof of descent from the recipient of a grant of arms made more than three hundred years before the date of application is required for Honor and Devotion; while only one hundred years is required for Grace and Devotion.
 Knights of Justice may be divided into those who have made simple vows and those who have made perpetual vows. The requirements and obligations of knights of Justice are dealt with by Chapters III through five and articles 14 through 102 of the Code. The first of these states: "Any Catholic man may be admitted to the First Class who: (a) is not subject to any legitimate impediment; (b) is moved by the right intention; (c) is capable of serving the sick and poor of Jesus Christ by dedicating himself to the service of the Church and of the Holy See according to the spirit of the Order". To make perpetual profession the knights must be at least 34 years of age, be admitted by the Grand Master with the consultative vote of the Sovereign Council on presentation by the appropriate Prior and Chapter (if such exists), have the approval of the Holy See, make profession freely as prescribed by Canon Law, and be received by the Grand Master or Prior or someone delegated by either of them (article 57). Perpetual vows may be made by a man of forty or older after three years in simple vows. The three religious vows promised by professed knights are vows of Obedience ("moving the soul to the imitation of Jesus Christ which renders it obedient even unto the death of the Cross" article 73) by which the knight is obliged to subordinate himself to his legitimate religious superior (article 74); of Chastity ("obliges the Professed also by virtue of religion to live celibately and to avoid every internal or external act contrary to Christian purity"); and of poverty (by which "the Professed renounces the free use of temporal goods" and while in simple vows he "retains the ownership of his property and the capacity to acquire other property", after making perpetual vows the Professed must make a Will disposing of his present and future property which cannot be modified without the permission of the Holy See or, in emergency, his religious superiors).
 Knights of Obedience "obligate themselves by a special promise, binding in conscience, to a life leading to Christian perfection, according to their own state of life, in the spirit of the Order and in the field of its works in conformity with the prescriptions belonging to them and to the directives of their legitimate superiors (Code, article 107, para 1) ...... (and) undertake to utilize their temporal goods according to the spirit of the Gospel" (article 107, para 2). To comply with the requirements for admission (by article 108) they must (a) profess the Catholic Religion, (b) not be the subject of canonical or moral impediment, (c) be at least 22 years of age, (d) have been a member for at least one year, (e) be qualified for the ranks of Honor or Grace and Devotion (the first and third rank of the third class). The Holy See must give permission for each postulant for Obedience to be received as such. There is a proposal presently awaiting consideration by the forthcoming Chapter-General for dames of the Order to be permitted to enter the class of Obedience.
 Only two have ever enjoyed a position on the Sovereign Council; in the 1970's the sometime Grand Chancellor, Quentin Gwyn, a knight of Obedience, was a Canadian, and Dr John MacPherson, a knight of Justice and former President of the Canadian Association, is presently a member of the Sovereign Council.
 Code of the Sovereign Military Hospitaller Order of St John of Jerusalem, of Rhodes and of Malta, Rome, 1966, p. 32, Chapter VIII, Articles 126 and 128.
 Code, p. 33, Chapter VIII, Article 130.
Fonte - http://www.chivalricorders.org/