A valid visa is not a guarantee of entry to Israel. You may have to satisfy other legal requirements.
Third-country nationals may be allowed to enter Israel if they:
Possess a valid travel document which allows its holder to cross borders;
Possess a valid visa, if required;
Justify the purpose and conditions of their intended stay and have sufficient means of subsistence both during their intended stay and for return to their country of origin or transit to a third country;
Do not have an alert issued for them to refuse entry;
Are not considered to be a threat to public policy, international security, public health, or international relations.
This means that a police officer, during border control, may ask you to present both notifications and documents that justify the purpose and conditions of your stay in Israel and the evidence that you have sufficient means of subsistence.