Q: Is any man able perfectly to keep the commandments of God?
A: No mere man, since the fall, is able, in this life, perfectly to keep the commandments of God; but doth daily break them, in thought, word, and deed.

1 Kings 8:46. If they sin against thee, (for there is no man that sinneth not), and thou be angry with them, and deliver them to the enemy, so that they carry them away captives unto the land of the enemy, far or near.
Ecclesiastes 7:20. For there is not a just man upon earth, that doeth good, and sinneth not.
1 John 1:8. If we say that we have no sin, we deceive ourselves, and the truth is not in us
1 John 1:10. If we say that we have not sinned, we make him a liar, and his word is not in us.
Galatians 5:17. For the flesh lusteth against the Spirit, and the Spirit against the flesh: and these are contrary the one to the other: so that ye cannot do the things that ye would.
Genesis 6:5. And God saw that the wickedness of man was great in the earth, and that every imagination of the thoughts of his heart was only evil continually.
Genesis 8:21. And the Lord smelled a sweet savour; and the Lord said in his heart, I will not again curse the ground any more for man's sake; for the imagination of man's heart is evil from his youth; neither will I again smite any more every thing living, as I have done.
Romans 3:9. What then? are we better than they? No, in no wise: for we have before proved both Jews and Gentiles, that they are all under sin.
James 3:8. The tongue can no man tame: it is an unruly evil, full of deadly poison.
James 3:2. For in many things we offend all. If any man offend not in word, the same is a perfect man, and able also to bridle the whole body.

Westminster Project - For more detail on question 82, see Matthew Henry's Scripture Catechism that follows the form of the WSC