يا أيها...

[Karim]

assalamu allaikum wa rahmatu allahi wa barakatuhu

ya ayuha is normally used, when the noun following is definite, that is what i know. but now im a little bit confuses, because of a sentence in madinnah book 2 page 186 you can find the following: تب إلى الله أيها المسلم
this sentence is without the ya....in kuran i alway hear ayuha with combination of ya. can we select what we want to write or is here a grammatical reason for?


and by the way, what is the meaning of "ma ila dalika", can we translated as "and so on"?