Because they regard not the works of the Lord - What the Lord does in creation; in his providence; through His commands and laws; and by His Spirit. They do not find pleasure in His works; they do not give heed to the intimations of His will in His providential dealings; they do not listen to His commands; they do not yield to the influences of His Spirit. “Nor the operation of his hands.” What He is now doing. The sense is essentially the same as in the former member of the sentence.
He shall destroy them - He will pull them down, instead of building them up. They expose themselves to His displeasure, and He will bring deserved punishment upon them.
And not build them up - He will not favor them; He will not give them prosperity. Health, happiness, salvation are to be found only in conformity with the laws which God has ordained. Neither can be found in violating those laws, or in any other method than that which He has ordained. Sooner or later the violation of law, in regard to these things, and in regard to everything, must lead to calamity and ruin.