(1.) In order to this he sets before them the difficulties of religion, and that in it which might be thought discouraging (v. 19, 20): You cannot serve the Lord, for he is a holy God, or, as it is in the Hebrew, he is the holy Gods, intimating the mystery of the Trinity, three in one; holy, holy, holy, holy Father, holy Son, holy Spirit. He will not forgive. And, if you forsake him, he will do you hurt. Certainly Joshua does not intend hereby to deter them from the service of God as impracticable and dangerous. But, [1.] He perhaps intends to represent here the suggestions of seducers, who tempted Israel from their God, and from the service of him; with such insinuations as these, that he was a hard master, his work impossible to be done, and he not to be pleased, and, if displeased, implacable and revengeful,—that he would confine their respects to himself only, and would not suffer them to show the least kindness for any other,—and that herein he was very unlike the gods of the nations, which were easy, and neither holy nor jealous. It is probable that this was then commonly objected against the Jewish religion, as it has all along been the artifice of Satan every since he tempted our first parents thus to misrepresent God and his laws, as harsh and severe; and Joshua by his tone and manner of speaking might make them perceive he intended it as an objection, and would put it to them how they would keep their ground against the force of it. Or, [2.] He thus expresses his godly jealousy over them, and his fear concerning them, that, notwithstanding the profession they now made of zeal for God and his service, they would afterwards draw back, and if they did they would find him just and jealous to avenge it. Or, [3.] He resolves to let them know the worst of it, and what strict terms they must expect to stand upon with God, that they might sit down and count the cost. "You cannot serve the Lord, except you put away all other gods for he is holy and jealous, and will by no means admit a rival, and therefore you must be very watchful and careful, for it is at your peril if you desert his service; better you had never known it." Thus, though our Master has assured us that his yoke is easy, yet lest, upon the presumption of this, we should grow remiss and careless, he has also told us that the gate is strait, and the way narrow, that leads to life, that we may therefore strive to enter, and not seek only. "You cannot serve God and Mammon; therefore, if you resolve to serve God, you must renounce all competitors with him. You cannot serve God in your own strength, nor will he forgive your transgressions for any righteousness of your own; but all the seed of Israel must be justified and must glory in the Lord alone as their righteousness and strength," Isa. xlv. 24, 25. They must therefore come off from all confidence in their own sufficiency, else their purposes would be to no purpose. Or, [4.] Joshua thus urges on them the seeming discouragements which lay in their way, that he might sharpen their resolutions, and draw from them a promise yet more express and solemn that they would continue faithful to God and their religion. He draws it from them that they might catch at it the more earnestly and hold it the faster.