Where in the Bible does it say you can't keep sinning and asking for forgiveness?

Some pertinent passages: Romans 6:1, 2 - What shall we say then? Shall we continue in sin that grace may abound? Certainly not! How shall we who died to sin live any longer in it? Hebrews 10:26, 27 - For if we sin willfully after we have received the knowledge of the truth, there no longer remains a sacrifice for sins, but a certain fearful expectation of judgment, and fiery indignation which will devour the adversaries. Galatians 6:7 - Do not be deceived, God is not mocked; for whatever a man sows, that he will also reap.To fall into a repetitive pattern of sinning and asking forgiveness is to "mock" God in that it is hypocritical, and tests His willingness to forgive. Matthew 4:7 - Jesus said to him, "It is written again, 'You shall not tempt ["test" or "try"] the Lord your God.' " [Quotes from NKJV]