To understand - Rather, "to consider."

And on the second day were gathered together,.... The second day of the month, and of the new year, the day after the feast of blowing of trumpets, and after the law had been read and explained:

the chief of the fathers of all the people: heads of tribes and families: the priests and the Levites; who, though they were instructors of others, needed to be taught themselves, of which they were sensible: and therefore came

unto Ezra the scribe, even to understand the words of the law; some things in it, which, upon reading the day before, they observed had some difficulty in them, and which they did not clearly and thoroughly understand; and therefore applied to Ezra, a ready scribe in the law, for better information, and that they might be better able to teach the people; which was highly commendable in them.

Celebration of the feast of tabernacles. - Nehemiah 8:13 On the second day were gathered together the heads of the houses of all the people, of the priests, and of the Levites to Ezra the scribe, to attend to the words of the law. The infinitive להשׂכּיל may indeed be taken (as by Bertheau) as the continuation of the finite verb, instead of as infinitive absolute (Ewald, 352, c); this is, however, admissible only in cases where the second verb either states what must be done, or further describes the condition of affairs, while להשׂכּיל here states the purpose for which the heads of the people, etc. assembled themselves unto Ezra. Hence we take להשׂכּיל in its usual meaning, and the w before it as explicative. אל השׂכּיל, as in Psalm 41:1, expresses taking an attentive interest in anything. They desired to be further and more deeply instructed in the law by Ezra.

And on the second day were gathered together the chief of the fathers of all the people, the priests, and the Levites, unto Ezra the scribe, even to understand the words of the law.

8:13 Levites - Chusing rather to confess their ignorance than vainly to pretend to more knowledge than they had: wherein they shew both humility, and serious godliness, that they were more careful to learn their duty than to preserve their reputation.

to understand...: or, that they might instruct in the words of the law

8:13-18 They found written in the law about the feast of tabernacles. Those who diligently search the Scriptures, find things written there which they have forgotten. This feast of tabernacles was a representation of the believer's tabernacle state in this world, and a type of the holy joy of the gospel church. The conversion of the nations to the faith of Christ, is foretold under the figure of this feast, Zec 14:16. True religion will render us strangers and pilgrims upon earth. We read and hear the word acceptably and profitably, when we do according to what is written therein; when what appears to be our duty is revived, after it has been neglected. They minded the substance; else the ceremony had been of no use. They did it, rejoicing in God and his goodness. These are the means which the Spirit of God crowns with success, in bringing the hearts of sinners to tremble and to become humbled before God. But those are enemies to their own growth in holiness, who always indulge sorrow, even for sin, and put away from them the consolations tendered by the word and Spirit of God.