Greeting the non-Muslims on Christmas and other religious holidays like Thanksgiving is prohibited by consensus because it implies that one accepts or approves of their rituals of disbelief, even if one would not accept those things for oneself.

It is not permissible to join in the non-Muslim festivals because this entails imitating or resembling them and taking part in their festivals is a kind of befriending them and showing love for them.

It is not permissible to eat from the food which the Christians or non-Muslims prepare on Christmas or other festivals. It is also not permissible to accept their invitations to join them in their celebrations.

It is not permissible for the Muslim to eat foods that the Jews, Christians and disbelievers make for their festivals. It is also not permissible to give them anything on the occasion of their festivals.

There is no report from the Prophet Muhammad (peace and blesisngs be upon him) to suggest that there is any particular virtue in performing ‘Umrah in Rajab, or that it is encouraged. For more, please see the detailed answer.

Salat al-Raghaib is a bid`ah that has been introduced in Rajab. It is done on the night of the first Friday in Rajab, between Maghrib and `Isha, and is preceded by fasting on the first Thursday of Rajab.

There is no sound hadith to indicate that there is any special virtue in fasting in Rajab. But there is a report from the Prophet (peace and blessings be upon him) which indicates that it is recommended to fast during the sacred months. For more, please see the detailed answer.

It is permissible in Islam for men and women to wear silver rings. There is no basis for the belief that wearing silver rings in Rajab will get one closer to Allah.