From BiblePortal Wikipedia

Hawker's Poor Man's Concordance And Dictionary [1]

In the margin of some of our Bibles, the translators have given the English of this name, as it is of several words, and they render it, making speed to the spoil; or he hasteneth to the prey.

And when we consider that the prophet was commanded to mark the roll of the prophecy then delivered by this name, and also called the child he had by the prophetess by the same name, no doubt the matter became very significant.

I would only detain the reader for one short observation upon it, just to remark, how very earnest the Lord's people were to carry, in the names of their children, continual records of the Lord's providences and dispensation. The prophet's son never heard himself called by this name, but it served to remind every faithful Israelite that heard it, of the Lord's hastening his purposes of redemption. And though the captivity of Babylon lay between, yet the glorious redemption from sin, death, hell, and the grave, by the Lord Jesus Christ, was seen beyond it. Hence faithful men were taken by the prophet to witness the record. (See  Isaiah 8:1; Isa 8:3;  Psalms 76:4)

Fausset's Bible Dictionary [2]

("hasteth to the spoil, speedeth to the prey".) As Immanuel, Isaiah's ( Isaiah 7:14;  Isaiah 8:1-4) first son by the virgin, was the sign of Judah's deliverance, so Maher-shalal-hash-baz the second son is the sign of destruction to Judah's enemies, Syria and Samaria. (See Immanuel .) Assyria will speedily spoil these. The prophet was to write Maher-shalal-hash-baz in a great roll with a man's pen, i.e. in ordinary characters, large enough for all to read, that after the event its correspondence to the prediction might be seen. Shearjashub ( Isaiah 7:3, "a remnant shalt return") was another sign that Judah should not be utterly destroyed, notwithstanding its terrible defeat by Pekah of Israel, and notwithstanding Syria's confederacy with Israel against it ( Isaiah 7:17-25;  Isaiah 8:6-9).

Hastings' Dictionary of the Bible [3]

Maher-Shalal-Hash-Baz (‘spoil speedeth, prey hasteth’),   Isaiah 8:1;   Isaiah 8:3 . A symbolical name given to one of Isaiah’s sons to signify the speedy destruction of the power of the allied kings Rezin and Pekah by the king of Assyria.

Smith's Bible Dictionary [4]

Ma'her-shal'al-hash'-baz. ( that is, Hasten-Booty Speedspoil). Whose name was given, by divine direction, to indicate that Damascus and Samaria were soon to be plundered by the king of Assyria.  Jeremiah 8:14.

American Tract Society Bible Dictionary [5]

Haste, spoil, speed to the prey, the name given by Isaiah to one of his sons, for a prophetic intimation of the speedy victory of the Assyrians over Syria and Israel,  Isaiah 8:1-3 .

Easton's Bible Dictionary [6]

 Isaiah 8:1-3 Zephaniah 1:14 Isaiah 8:1,3

Cyclopedia of Biblical, Theological and Ecclesiastical Literature [7]

(Heb. Maher'-Shalal'-Chash-Baz, מִהֵר שָׁלָל חָשׁ בִּז , Speeding for Booty He Hastes to the Spoil; Sept. Ὀξέως Προνομὴν Ποιῆσαι Σκύλων and Ταχέως Σκύλευσον , Ὀξέως Προνόμευσον ,Vulg. Velociter spolia detsrahe, cito praemdare and Accelera Spolia Detrahere, Festiia Pracedsci; for the grammatical construction, see Gesenius, Comment. ad loc.), words which the prophet Isaiah was first commanded to write in large characters upon a tablet, n and afterwards to give as a symbolical name to a son that was to be born to him ( Isaiah 8:1;  Isaiah 8:3). as prognostic of the sudden attack of Damascus and Syria by the Assyrian army (see Henderson's Comment. ad loc.). The child in question was evidently the prophet's son by "the prophetess" whom he espoused in pursuance of the divine mandate, and appears to have been the same with the one whose birth under the more Messianic title of IMMANUEL was at once a token to Ahaz of the coming defeat of his enemies ( Isaiah 7:14-16), and an illustrious type of Gospel deliverance. B.C. 739.

International Standard Bible Encyclopedia [8]

mā´hẽr - shal´al - hash´baz ( בּז חשׁ שׁלל מהר , mahēr shālāl ḥāsh baz , "the spoil speedeth; the prey hasteth"): Asymbolic name given to Isaiah's son to signify the sharp destruction of Rezin and Pekah by the Assyrian power (  Isaiah 8:1 ,  Isaiah 8:3 ). Compare the Greek idea of Nemesis.

Kitto's Popular Cyclopedia of Biblial Literature [9]

Maher-shalal-hash-baz, words prognostic of the sudden attack of the Assyrian army ('he hasteth to the spoil'), which the prophet Isaiah was first commanded to write in large characters upon a tablet, and afterwards to give as a symbolical name to a son that was to be born to him . It is, as Dr. Henderson remarks, the longest of any of the Scripture names, but has its parallels in this respect in other languages, especially in our own during the time of the Commonwealth.