Be ye therefore very courageous to keep and to do, etc. - It requires no small courage to keep a sound creed in the midst of scoffers, and not less to maintain a godly practice among the profane and profligate.

That is written in the book - By the word of God alone his followers are bound. Nothing is to be received as an article of faith which God has not spoken.

Be ye therefore very courageous to keep and to do all that is written in the book of the law of Moses,.... To observe which required spiritual strength, fortitude of mind, a holy courage, a firm and fixed resolution, and particularly to destroy the Canaanites required in that book, and to abstain from all communion and fellowship with them:

that ye turn not aside therefrom, to the right hand or the left; See Gill on Joshua 1:7.

Only let them be strong, i.e., be brave, to keep the law of Moses without fail (cf. Joshua 1:7), to enter into no fellowship with these remaining nations (בּוא, to enter into close intimacy with a person; see Joshua 23:12), and not to pay reverence to their gods in any way, but to adhere stedfastly to the Lord their God as they had hitherto done. To make mention of the names of the idols (Exodus 23:13), to swear by them, to serve them (by sacrifices), and to bow down to them (to invoke them in prayer), are the four outward forms of divine worship (see Deuteronomy 6:13; Deuteronomy 10:20). The concluding words, "as ye have done unto this day," which express a reason for persevering in the attachment they had hitherto shown to Jehovah, "do not affirm that the Israelites had hitherto done all these things fully and perfectly; for who does not know how few mortals there are who devote themselves to God with all the piety and love which He justly demands? But because the nation as a whole had kept the laws delivered to them by Moses, during the time that the government had been in the hands of Joshua, the sins of individual men were left out of sight on this occasion" (Masius).

Be ye therefore very courageous to keep and to do all that is written in the book of the law of Moses, that ye turn not aside therefrom to the right hand or to the left;

23:6 Very courageous - For it will require great courage and resolution to execute all the commands of Moses, and particularly, that of expelling and destroying the residue of the Canaanites. The right hand or the left - That is, in one kind or other, by adding to the law, or diminishing from it.

23:1-10 Joshua was old and dying, let them observe what he said now. He put them in mind of the great things God had done for them in his days. He exhorted them to be very courageous. Keep with care, do with diligence, and regard with sincerity what is written. Also, very cautiously to endeavour that the heathen idolatry may be forgotten, so that it may never be revived. It is sad that among Christians the names of the heathen gods are so commonly used, and made so familiar as they are. Joshua exhorts them to be very constant. There might be many things amiss among them, but they had not forsaken the Lord their God; the way to make people better, is to make the best of them.