Isaiah 42:21 - Matthew Poole's English Annotations on the Holy Bible

Is well-pleased, to wit, with you; or, as this word is most commonly used, hath a good-will to you or to this people; which may be understood out of the following verse, as is very usual in sacred Scripture. The meaning seems to be this; Although thou art a wicked people, that rebellest against the clearest light, and therefore God might justly destroy thee suddenly; yet he is very unwilling to do it, and will patiently wait for thy repentance, that he may be gracious unto thee. For his righteousness sake; not for thy sake, for thou deservest no such thing from him, but for the glory of his own faithfulness, in fulfilling that promise and covenant which he made with thy pious progenitors for themselves and for their seed. He will magnify the law, and make it honourable; he will maintain the honour of his law, and therefore is not forward to destroy you, who profess God's law, and the true religion, lest his law should upon that occasion be exposed to contempt.