Is any man able perfectly to keep the commandments of God?

Answer

No mere man, since the Fall, is able in his life to keep the commandments of God perfectly (), but daily breaks them in thought (), word (), and deed ().

Read the 4 proof texts (KJV)

Ecclesiastes 7:20: For [there is] not a just man upon earth, that doeth good, and sinneth not.
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.
James 3:8: But 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.