C that hour, when it is time for prayer, (ie the beginning of the dawn), it is forbidden to man to go to his friend to say hello to him. Anyone who is in the synagogue, and comes with its permanent location to a friend or a friend, to greet him, too, must be aware of this ban.


Besides, who does not go to his friend, and sets him on the road, it is not forbidden to greet him any greeting, except for the word "shalom". The word "Shalom" greeting in this case should not be, because this word is the name of the Creator, and it is not proper to mention in relation to the other person until you have prayed to the Creator and give Him honor.


In accordance with the letter of the law, a person walking on the road and met a neighbor, it is not forbidden to greet him, and the word "shalom". However, it should not use the common greeting (for example, "Let it be your good morning!"), So as to emphasize that it has not yet prayed, and remind himself and his neighbor that is forbidden to do some business before the prayer.


Rav Reuven Kuklin

http://www.imrey.org/2017/07/12/запрет-здороваться-до-молитвы/