What is the meaning of "u'Maltem es Orlas Levavchem!"?
Rashi: It means 'Remove that which stops up the heart and blocks it!' - from understanding the words of Hashem. 1
Seforno: It means 'Remove the foreskin (the blockage) of the intellect - erroneous thoughts that create warped Hashkafos (outlook - opinions).
Targum Onkelos and Targum Yonasan: It means 'Remove the foolishness of your hearts!'.
What are the implications of "ve'Orp'chem Lo Sakshu Od!"?
Ramban: It implies that they should stop being stubborn like their fathers, who learned from the Egyptians and were incapable of changing their ways, causing them t commit the sin of the Eigel ha'Zahav, following which Hashem called them "Am K'shei Oref". 1
Seforno: 'And cease being stubborn' - thereby enabling you to turn towards acknowledging your Creator and seeing how bitter it is to Forsake Him.
See Ramban who elaborates.