Shaykh Muhammad ibn ‘Uthaymeen (may Allaah have mercy on him) said:
There is nothing wrong with saying to someone “I urge you” concerning a matter in which he can do something to help you.
Similarly it is acceptable to say “I send you my greetings” and the like, because Allaah says (interpretation of the meaning):
“When you are greeted with a greeting, greet in return with what is better than it, or (at least) return it equally”
[al-Nisa’ 4:86]
The words “Good morning” and “Good evening” are also acceptable, so long as they are not taken as an alternative to the greeting of salaam that is prescribed in sharee’ah.