Peace be upon you
The previous ayaa is "But they say, "Why are not signs sent down to him from his Lord?" Say, "The signs are only with God , and I am only a clear warner.", then the next ayaa says "And is it not sufficient for them that We revealed to you the Book which is recited to them?"
This is clearly a response to the claim that the Prophet (PBUH) did not have any signs, and God responds that is not enough that a book is revealed to him. This ayaa cannot mean that we are not allowed to read other religious books.
Hope that answers your question.