What is the ruling on saying "A morning of obedience and faith"?

There is no objection to greeting with "Good morning" or "Good evening," but it should not replace the Islamic greeting "Assalamu Alaykum." It is preferred to begin with the Islamic greeting, and then one may add similar greetings. "Assalamu Alaykum" is a prayer for the Muslim for safety from worldly and religious afflictions, and it should be given precedence over other greetings.