They shall suffer "for righteousness" sake; but he then passes over, from the general idea of the kingdom (righteousness -- holiness) to his own person: "Blessed are ye when men shall revile you, &c., for My sake." Their very relations to Him were to draw upon them all manner of slanders and calumnies; thus presupposing that the prevailing Jewish opinions would be opposed by his disciples. 
The accompanying beatitudes are also full of meaning. "Blessed are the peace-makers, for they shall be called  the children of God," that is, shall be invested with the dignity and the rights of children of God. This promise refers partly to the present life, and partly, in its highest meaning, to the future.  "Blessed are they which are persecuted, for theirs is the kingdom of heaven." . . . "For great is your reward in heaven."
The "reward" may be understood, even apart from what Christ has said elsewhere, from the connexion of this discourse itself.  The first beatitudes show that we have no claim to the kingdom but our humble wants and susceptible hearts; the idea of merit, therefore, claiming a reward as its due, is wholly out of the question. The reward is a gracious gift. But when grace has admitted us into the kingdom, our participation in its "blessedness" depends upon our bearing in the struggles to which our membership in the kingdom exposes us on earth. The "reward," therefore, designates the relation between the Divine gifts and our subjective worth; the gifts are proportioned to the work which the members of the kingdom, as such, have to do.  It is obvious, then, that no external reward is meant -- no acting with a view to such -- for these ideas are foreign to the nature of the kingdom of God itself.
What, then, is the "reward?" It is, that the wants of our higher nature shall be satisfied; that we shall enjoy perfect communion with God, and, in consequence, perfect knowledge of him; that we shall have, and exercise, the perfect privilege of sons of God. It is nothing but the perfect realization of what is implied in "the kingdom," "the children of God," "the Divine life." In our struggles for the kingdom, we must direct our eye to the goal of the consummation; must feel that we struggle for no vain ideal. The two expressions "reward in heaven," and "inherit the earth," mutually illustrate each other; the latter is to be a spiritual, and not a carnal, Jewish, world-dominion; the former does not betoken a locality, but a perfected communion of life with God, i. e., a Divine life brought to perfection.
 This agrees very well with the point of time to which we have referred the Sermon on the Mount, i. e., the period when the Pharisees began to persecute Christ and his disciples. Moreover, his foresight at that time of the hatred he would excite, and the persecutions his followers would suffer, combined with the fact that throughout the discourse there is not the slightest hint of a purpose to triumph over his foes by an overwhelming miraculous power--nay, that the whole spirit of the discourse is opposed to such a purpose--agrees very well with his anticipating, at the time, that he should die in fulfilling his calling.  The name is the outward sign of the thing--its manifestation and confirmation.  Indicated in klethesontai, especially.  Cf. De Wette's excellent remarks on Matt., v., 12.  Cf. Nitzch's striking observations on the Divine Justice and Rewards, System der Christlichen Lehre, p. 115, 2d ed.
 The name is the outward sign of the thing--its manifestation and confirmation.
 Indicated in klethesontai, especially.
 Cf. De Wette's excellent remarks on Matt., v., 12.
 Cf. Nitzch's striking observations on the Divine Justice and Rewards, System der Christlichen Lehre, p. 115, 2d ed.