Daniel shall be a serpent - The original word is נחש nachash, and we have seen on Genesis 3 that this has a great variety of significations. It is probable that a serpent is here intended, but of what kind we know not; yet as the principal reference in the text is to guile, cunning, etc., the same creature may be intended as in Genesis 3.
A cerastes upon the track - The word שפיפון shephiphon, which is nowhere else to be found in the Bible, is thus translated by the Vulgate, and Bochart approves of the translation. The cerastes has its name from two little horns upon its head, and is remarkable for the property here ascribed to the shephiphon. The word ארח orach, which we translate path, signifies the track or rut made in the ground by the wheel of a cart, wagon, etc. And the description that Nicander gives of this serpent in his Theriaca perfectly agrees with what is here said of the shephiphon.
εν δ' αμαθοισιν
Η και ἁματροχιῃσι παρα στιβον ενδυκες ανει.
v. 262.
It lies under the sand, or in some cart rut by the way.
It is intimated that this tribe should gain the principal part of its conquests more by cunning and stratagem, than by valor; and this is seen particularly in their conquest of Laish, Judges 18, and even in some of the transactions of Samson, such as burning the corn of the Philistines, and at last pulling down their temple, and destroying three thousand at one time, see Judges 16:26-30.
18. For thy salvation have I waited, O Lord!
This is a remarkable ejaculation, and seems to stand perfectly unconnected with all that went before and all that follows; though it is probable that certain prophetic views which Jacob now had, and which he does not explain, gave rise to it; and by this he at once expressed both his faith and hope in God. Both Jewish and Christian commentators have endeavored to find out the connection in which these words existed in the mind of the patriarch. The Targum of Jonathan expresses the whole thus: "When Jacob saw Gideon the son of Joash, and Samson the son of Manoah, which were to be saviors in a future age, he said: I do not wait for the salvation of Gideon, I do not expect the salvation of Samson, because their salvation is a temporal salvation; but I wait for and expect thy salvation, O Lord, because thy salvation is eternal." And the Jerusalem Targum much to the same purpose: "Our father Jacob said: Wait not, my soul, for the redemption of Gideon the son of Joash which is temporal, nor the redemption of Samson which is a created salvation; but for the salvation which thou hast said by Thy Word should come to thy people the children of Israel: my soul waits for this thy salvation." Indeed these Targums understand almost the whole of these prophecies of the Messiah, and especially what is said about Judah, every word of which they refer to him. Thus the ancient Jews convict the moderns of both false interpretations and vain expectations. As the tribe of Daniel was the first that appears to have been seduced from the true worship of God, (see Judges 18:30), some have thought that Jacob refers particularly to this, and sees the end of the general apostasy only in the redemption by Jesus Christ, considering the nachash above as the seducer, and the Messiah the promised seed.
19. Gad, an army shall attack him, And he shall attack in return.
This is one of the most obscure prophecies in the whole chapter; and no two interpreters agree in the translation of the original words, which exhibit a most singular alliteration: - גד גדוד יגודנו gad gedud yegudennu; והוא יגד עקב vehu yagud akeb.
The prophecy seems to refer generally to the frequent disturbances to which this tribe should be exposed, and their hostile, warlike disposition, that would always lead them to repel every aggression. It is likely that the prophecy had an especial fulfillment when this tribe, in conjunction with that of Reuben and the half tribe of Manasseh, got a great victory over the Hagarites, taking captive one hundred thousand men, two thousand asses, fifty thousand camels, and two hundred and fifty thousand sheep; see 1-Chronicles 5:18-22. Dr. Durell and others translate the last word עקב akeb, rear - "He shall invade their rear;" which contains almost no meaning, as it only seems to state that though the army that invaded Gad should be successful, yet the Gadites would harass their rear as they returned: but this could never be a subject sufficient consequence for a prophecy. The word עיב d ekeb is frequently used as a particle, signifying in consequence, because of, on account of. After the Gadites had obtained the victory above mentioned, they continued to possess the land of their enemies till they were carried away captive. The Chaldee paraphrasts apply this to the Gadites going armed over Jordan before their brethren, discomfiting their enemies, and returning back with much spoil. See Joshua 4:12, Joshua 4:13, and Joshua 22:1-2, Joshua 22:8.
20. From Asher his bread shall be fat, And he shall produce royal dainties.
This refers to the great fertility of the lot that fell to Asher, and which appears to have corresponded with the name, which signifies happy or blessed. His great prosperity is described by Moses in this figurative way: "Let Asher be blessed with children, let him be acceptable to his brethren, and let him dip his foot in oil;" Deuteronomy 33:24.
21. Naphtali is a spreading oak, Producing beautiful branches.
This is Bochart's translation; and perhaps no man who understands the genius of the Hebrew language will attempt to dispute its propriety; it is as literal as it is correct. Our own translation scarcely gives any sense. The fruitfulness of this tribe in children may be here intended. From his four sons Jahzeel, Guni, Jezer, and Shillem, which he took down into Egypt, Genesis 46:24, in the course of two hundred and fifteen years there sprang of effective men 53,400: but as great increase in this way was not an uncommon case in the descendants of Jacob, this may refer particularly to the fruitfulness of their soil, and the especial providential care and blessing of the Almighty; to which indeed Moses seems particularly to refer, Deuteronomy 33:23 : O Naphtali, satisfied with favor, and full with the blessing of the Lord. So that he may be represented under the notion of a tree planted in a rich soil, growing to a prodigious size, extending its branches in all directions, and becoming a shade for men and cattle, and a harbour for the fowls of heaven.
22. The son of a fruitful (vine) is Joseph; The son of a fruitful (vine) by the fountain: The daughters (branches) shoot over the wall.
23. They sorely afflicted him and contended with him; The chief archers had him in hatred.
24. But his bow remained in strength, And the arms of his hands were made strong By the hand of the Mighty One of Jacob: By the name of the Shepherd, the Rock of Israel.
25. By the God of thy father, for he helped thee; And God All-sufficient, he blessed thee, The blessing of the heavens from above, And the blessings lying in the deep beneath, The blessings of the breasts and of the womb
26. The blessings of thy father have prevailed Over the blessings of the eternal mountains, And the desirable things of the everlasting hills. These shall be on the head of Joseph, And on his crown who was separated from his brethren.

Daniel shall be a serpent by the way, an adder in the path,.... Or be like that sort of serpents called the adder; or rather, that which has the name of Cerastes, which lies among sand, and being of the same colour is not easily discerned, and is often trampled upon unawares, and bites at once, unexpected; as Bothart (h) from various writers has shown; particularly Diodorus Siculus (i) says, of this kind of serpents, that their bites are deadly, and being of the same colour with the sand, few discern them, so that many ignorantly treading on them fall into danger unawares; and so Onkelos paraphrases it, that lies in wait by the way; and is by another writer (k) interpreted, a very grievous and hurtful serpent as the adder is:
that biteth the horse heels, so that his rider shall fall backward; for this sort of serpents lying in horse ways and cart ruts, snaps at and bites horses as they pass along, which bites affecting their legs and thighs, cause them to fall and throw their riders: this, by the Jewish writers, who are followed by many Christian interpreters, is applied to Samson, who by craft and policy managed the Philistines, as in the affair of the foxes, and especially in his last enterprise, when he got placed between the two pillars of the house, which answer, as some think, to the horse heels, as the multitude on the roof of the house to the riders: but though this may be illustrated in a particular person in this tribe, as a specimen of the genius and disposition of the whole tribe, yet the prophecy respects the whole tribe, and points at the situation of it, which was "by the way", at the extreme part of the country; so that they had need of craft and policy as well as power to defend themselves against encroachers and invaders, and describes the general temper and disposition of this tribe, of which an instance may be seen in Judges 18:1 and it may have respect to the stumblingblocks and offences laid in this tribe to the rest of the tribes, by the idol of Micah, and more especially by the golden calf set up in Daniel by Jeroboam.
(h) Hierozoic. par. 2. l. 3. c. 12. col. 418, 419, 420. (i) Bibliothec. l. 3. p. 183. (k) R. Song. Urbin. Ohel Moed. fol. 57. 1.

DAN--though the son of a secondary wife, was to be "as one of the tribes of Israel." (Genesis 49:16-18)
Daniel--"a judge."
a serpent . . . an adder--A serpent, an adder, implies subtlety and stratagem; such was pre-eminently the character of Samson, the most illustrious of its judges.