And the great Apostle protests that he has a continual sorrow in his heart,  for the obstinacy of the Jews.
Meanwhile, however obstinate sinners may be, let us never desist from aiding and assisting them. How do we know but that they may do penance and be saved? Happy is he that can say to his neighbour as did S. Paul: For three years I ceased not with tears to admonish every one of you night and day. Wherefore I take you to witness this day that I am clear from the blood of all men. For I have not spared to declare unto you all the counsel of God.  So long as we are within the limits of hope that the sinner will amend (which limits are always of the same extent as those of his life), we must never reject him, but pray for him and assist him as far as his misery will permit.
But, at last, after we have wept over the obstinate, and performed towards them the good offices of charity in trying to reclaim them from perdition, we must imitate our Saviour and the Apostles; that is, we must divert our spirit from thence and place it upon other objects and employments which are more to the advancement of God's glory. To you it behoved us first (said the Apostles to the Jews) to speak the word of God: but because you reject it, and judge yourselves unworthy of eternal life, behold we turn to the Gentiles.  The kingdom of God (said our Saviour) shall be taken from you, and shall be given to a nation yielding the fruits thereof.  For we cannot spend too long time in bewailing some, without losing time fit and necessary for procuring the salvation of others. The Apostle indeed says that the loss of the Jews is a continual sorrow to him, but this is said in the same sense that we say we praise God always; for we mean no other thing thereby than that we praise him very frequently, and on every occasion; and in the same manner the glorious St. Paul felt a continual grief in his heart on account of the reprobation of the Jews, in the sense that on every occasion he bemoaned their misfortune.
For the rest we must ever adore, love and praise God avenging and punishing justice as we love his mercy, being both daughters of his goodness; for by his grace he makes us good, being good, yea, sovereignly good, himself; by his justice he punishes sin because he hates it, and he hates it because, being sovereignly good, he hates the sovereign evil which is iniquity: and, in conclusion, note, that God never withdraws his mercy from us save by the just vengeance of his punishing justice, nor do we ever escape the rigour of his justice but by his justifying mercy: and always, whether punishing or favouring us, his good-pleasure is worthy of adoration, love and everlasting praise. So the just man who sings the praises of the mercy of God over such as shall be saved, will also rejoice when he shall see his vengeance. The blessed shall with joy approve the sentence of the damnation of the reprobate, as well as that of the salvation of the elect: and the angels, having exercised their charity towards those that they had in keeping, shall remain in peace, when they see them obstinate, yea even damned. We are therefore to submit ourselves to the Divine will, and kiss the right hand of his mercy and the left hand of his justice, with an equal love and reverence.