And Achan answered Joshua, and said, Indeed I have sinned against the LORD God of Israel, and thus and thus have I done:

Wesley's Notes

7:20 Indeed I have sinned - He seems to make a sincere and ingenuous confession, and loads his sin with all just aggravations. Against the Lord - Against his express command, and glorious attributes. God of Israel - The true God, who hath chosen me and all Israel to be the people of his peculiar love and care.

Matthew Henry's Concise Commentary

7:16-26 See the folly of those that promise themselves secrecy in sin. The righteous God has many ways of bringing to light the hidden works of darkness. See also, how much it is our concern, when God is contending with us, to find out the cause that troubles us. We must pray with holy Job, Lord, show me wherefore thou contendest with me. Achan's sin began in the eye. He saw these fine things, as Eve saw the forbidden fruit. See what comes of suffering the heart to walk after the eyes, and what need we have to make this covenant with our eyes, that if they wander they shall be sure to weep for it. It proceeded out of the heart. They that would be kept from sinful actions, must mortify and check in themselves sinful desires, particularly the desire of worldly wealth. Had Achan looked upon these things with an eye of faith, he would have seen they were accursed things, and would have dreaded them; but looking on them with an eye of sense only, he saw them as goodly things, and coveted them. When he had committed the sin, he tried to hide it. As soon as he had got this plunder, it became his burden, and he dared not to use his ill-gotten treasure. So differently do objects of temptation appear at a distance, to what they do when they have been gotten. See the deceitfulness of sin; that which is pleasing in the commission, is bitter in the reflection. See how they will be deceived that rob God. Sin is a very troublesome thing, not only to a sinner himself, but to all about him. The righteous God will certainly recompense tribulation to them that trouble his people. Achan perished not alone in his sin. They lose their own, who grasp at more than their own. His sons and daughters were put to death with him. It is probable that they helped to hide the things; they must have known of them. What fatal consequences follow, even in this world, to the sinner himself, and to all belonging him! One sinner destroys much good. What, then, will be the wrath to come? Let us flee from it to Christ Jesus as the sinner's Friend. There are circumstances in the confession of Achan, marking the progress of sin, from its first entrance into the heart to its being done, which may serve as the history of almost every offence against the law of God, and the sacrifice of Jesus Christ.