Therefore my people are gone - This is evidently used with reference to the "future." The prophet described events as "passing before his eyes" as a vision (note, Isaiah 1:1); and he here seems to "see" the people going into captivity, and describes it as an event actually occurring.

Into captivity - Referring, doubtless, to the captivity at Babylon.

Because they have no knowledge - Because they do not choose to retain the knowledge of God.

And their honorable men - The Hebrew is, 'The glory of the people became people of famine;' that is, they shall be destroyed with famine. This was to be a "punishment" for their dissipation at their feasts.

And their multitude - The mass, or body of the nation; the common people.

Dried up with thirst - Are punished in this manner for their indulgence in drinking. The punishment here specified, refers particularly to a journey through an arid, desolate region, where drink could be obtained only with difficulty. Such was the route which the nation was compelled afterward to take in going to Babylon.

Isaiah 5:13 Parallel Commentaries

Dishonest Tenants
'And He began to speak unto them by parables. A certain man planted a vineyard, and set an hedge about it, and digged a place for the winefat, and built a tower, and let it out to husbandmen, and went into a far country. 2. And at the season he sent to the husbandmen a servant, that he might receive from the husbandmen of the fruit of the vineyard. 3. And they caught him, and beat him, and sent him away empty. 4. And again he sent unto them another servant; and at him they cast stones, and wounded …
Alexander Maclaren—Expositions of Holy Scripture

Letter Xlviii to Magister Walter De Chaumont.
To Magister [75] Walter de Chaumont. He exhorts him to flee from the world, advising him to prefer the cause and the interests of his soul to those of parents. MY DEAR WALTER, I often grieve my heart about you whenever the most pleasant remembrance of you comes back to me, seeing how you consume in vain occupations the flower of your youth, the sharpness of your intellect, the store of your learning and skill, and also, what is more excellent in a Christian than all of these gifts, the pure and innocent …
Saint Bernard of Clairvaux—Some Letters of Saint Bernard, Abbot of Clairvaux

The Call of Isaiah
The long reign of Uzziah [also known as Azariah] in the land of Judah and Benjamin was characterized by a prosperity greater than that of any other ruler since the death of Solomon, nearly two centuries before. For many years the king ruled with discretion. Under the blessing of Heaven his armies regained some of the territory that had been lost in former years. Cities were rebuilt and fortified, and the position of the nation among the surrounding peoples was greatly strengthened. Commerce revived, …
Ellen Gould White—The Story of Prophets and Kings