I will give thee counsel. Jethro dares, indeed, to promise success, if Moses will obey his counsel; yet does he not proudly boast that this will be the fruit of his own prudence, but ascribes it to God's blessing and grace, if he prospers even when nothing is established but on the best system. For this is the import of the expression, that a counsel occurs to him, which if Moses follows, God shall bless him. Nor yet does he reprove Moses, as if God had not been thus far with his pious zeal and industry, but rather hints that God is the author of this counsel, which He will follow up with His grace. In sum, he does not state it to be his Object to diminish in the smallest degree the grace which Moses had already experienced; but to point out a plan, of which God will, by its result, show His approbation. Then follows the other point to which I have alluded, viz., that he does not rob Moses of his authority, so as to overturn his call from God, but rather by exhorting him to proceed, desires that what God has once ordained should be firm and inviolable. It is well also for us diligently to consider that counsel be taken according to circumstances and expediency, so that there be no departure from the ordinance of God; because it is sinful to entertain the question whether we should obey God or not. Accursed, then, are the deliberations wherein it is proposed to alter anything in God's Word, or to withdraw ourselves from the bounds of our calling. We have said that the burden whereby Moses was weighed down was not of God's imposing; but only had he been set over the people as their leader, as far as his ability permitted. Jethro leaves this unaffected, and thus confirms by subscribing, as it were, to the decree of heaven. Because he was chosen to be as an interpreter, and God familiarly admitted him as the mediator between Him and His people, Jethro enjoins him to continue in the discharge of these duties. But because the possession of the supreme government did not interfere with the duty of a Prophet, he desired also the greater matters to be referred to him; for I so interpret the expressions, that Moses was to be "to God-ward," for the delivery of the rule of piety, and for the performance of the prophetical office, whilst the weightier causes were to be referred by the rulers to him, that every one might have justice done him.

Counsel - Jethro draws the distinction between the functions of the legislator and the judge.
To God-ward - Literally, "before God," standing between them and God, both as His minister or representative and also as the representative of the people, their agent, so to speak, or deputy before God.

I will give thee counsel, and God shall be with thee - Jethro seems to have been a man of great understanding and prudence. His advice to Moses was most appropriate and excellent; and it was probably given under the immediate inspiration of God, for after such sacrificial rites, and public acknowledgment of God, the prophetic spirit might be well expected to descend and rest upon him. God could have showed Moses the propriety and necessity of adopting such measures before, but he chose in this case to help man by man, and in the present instance a permanent basis was laid to consolidate the union of the two families, and prevent all future misunderstandings.

Hearken now unto my voice, I will give thee counsel, and God shall be with thee: Be thou for the people to (h) God-ward, that thou mayest bring the causes unto God:
(h) You judge in difficult cases, which cannot be decided without consulting with God.

Hearken now unto my voice, I will give thee counsel,.... Jethro being the elder man, and of some character and figure, being either a priest or prince of Midian, or both, might, without incurring a censure, take upon him to give advice to Moses, a younger man, and his son-in-law, though he was superior to him in office and in parts; and especially since his advice proceeded from a sincere and cordial regard for his health and welfare:
and God shall be with thee: and succeed the advice he gave, which he persuaded himself would be agreeable to the will of God, and attending to it he would prosper, and find that the method taken would be blessed of God, and issue in his own good and the good of the people; or it may be taken prayerwise, as by some, "may God be with thee" (s); to direct thee to what thou shouldest do, either to take the advice, or reject it; and be it as it will, he wished him well, and that he might have his health, and that as his day was, his strength might be:
be thou for the people to God-ward; or on the part of God, as Aben Ezra interprets it; that part of his work he advised him to retain by all means, which lay more immediately between God and the people; to be a mediator between them; to transact affairs for them with God; to inquire his mind and will in matters difficult and doubtful; to be, as Jarchi expresses it, a messenger and interpreter between them, and an inquirer of judgments of him, or what statutes and judgments he would have observed by them: that thou mayest bring the causes unto God; concerning which, as yet, he had given no directions as a rule to go by.
(s) see Poole in loc.

Be thou for them to God - ward - That was an honour which it was not fit any other should share with him in. Also whatever concerned the whole congregation must pass through his hand, Exodus 18:20. But, he appointed judges in the several tribes and families, which should try causes between man and man, and determine them, which would be done with less noise, and more dispatch than in the general assembly. Those whose gifts and stations are most eminent may yet be greatly furthered in their work by the assistance of those that are every way their inferiors. This is Jethro's advice; but he adds two qualifications to his counsel. That great care should be taken in the choice of the persons who should be admitted into this trust; it was requisite that they should be men of the best character. For judgment and resolution, able men: men of good sense, that understood business; and bold men, that would not be daunted by frowns or clamours. Clear heads and stout hearts make good judges. For piety, such as fear God, who believe there is a God above them, whose eye is upon them, to whom they are accountable, and whose judgment they stand in awe of. Conscientious men, that dare not do an ill thing, though they could do it never so secretly and securely. For honesty, men of truth, whose word one may take, and whose fidelity one may rely upon. For a generous contempt of worldly wealth, hating covetousness, not only not seeking bribes, or aiming to enrich themselves, but abhorring the thought of it. That he should attend God's direction in the case, Exodus 18:23. If thou shalt do this thing, and God command thee so - Jethro knew that Moses had a better counsellor than he was, and to his counsel he refers him.