17....And he has done this; for he says how long labour is before him; “until I enter into the sanctuary of God, and understand upon the last things”. A great thing it is, brethren: now for a long time I labour, he says, and before my face I see a sort of insuperable labour, to know in what manner both God is just, and does care for things human, and is not unjust because men sinning and doing wicked actions have happiness on this earth; but the godly and men serving God are wasted ofttimes in trials and in labours; a great difficulty it is to know this, but only “until I enter into the Sanctuary of God.”
For in the Sanctuary what is presented to you, in order that you may solve this question? “And I understand,” he says, “upon the last things:” not present things. I, he says, from the Sanctuary of God stretch out my eye unto the end, I pass over present things. All that which is called the human race, all that mass of mortality is to come to the balance, is to come to the scale, thereon will be weighed the works of men. All things now a cloud does enfold: but to God are known the merits of each severally. “And I understand,” he says, “upon the last things:” but not of myself; for before me there is labour. Whence “may I understand upon the last things”? Let me enter into the Sanctuary of God. In that place then he understood also the reason why these men now are happy.
Source: The Enarrations, or Expositions, on the Psalms (New Advent)