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Yes he could, he had free will like the rest of us. But he loved God more than himself and denied sin in his flesh. So he came to be an example to us, so if we love God we will follow him and with his love fight sin within our own hearts. As he said to his disciples, "Be of good cheer, for I have overcome the world." (John 16:33). So he had freewill as he had to overcome sin and if we believe, he can (with the love of God) help us to overcome sin too!