9 The word sehr here does not mean magic but deception and fraud, which is also a well known meaning of this word in Arabic. Thus, the verse means: "When the Prophet whose coming had been foretold by the Prophet Jesus came with the clear signs of his prophethood, the Israelites and the followers of Jesus,declared his claim to Prophet hood to be a deception and fraud."
10 "... forges ... against Allah": declares the Prophet sent by Allah to be a false prophet and regards the Revelations of Allah to His Prophet as forged by the Prophet himself.
11 That is, there could be no greater in justice than that besides calling a true Prophet a false prophet, one should start hurling abuses on him and employing all sorts of lies and false allegations and slanders to defeat his mission although the Prophet is calling him to Allah's worship and His obedience.