There are quite a few expressions of greetings, holiday good wishes, and congratulations which consist of the preposition с plus Instrumental, such as С днём рождљния 'Happy birthday'. Some of them, illustrated below, have synonymous counterparts consisting of the Nominative case alone.
С днём рождљния! Happy birthday!
С Рождествћм (Христћвым)! Merry Christmas!
С Нћвым гћдом! Happy New Year!
С прђздником! Happy holiday!
С наступђющим! Happy holiday! (Lit. 'with the coming [holiday]')
С дћбрым џтром! ( = Дћброе џтро!) Good morning!
Дћбрый вљчер! Good evening!
Дћбрый дљнь! Hello! (said during the day)