We are not allowed to make a blanket statement to the effect that the expression yaa rasoola Allah by itself constitutes shirk: It can be considered shirk only if a person is uttering these words to pray to the Prophet, peace be upon him, or beech him for succor instead of Allah. Islam is emphatic on insisting that we must call upon none but Allah. This is the quintessence of tawhid as implied in the verse iyyaka na’budu wa iyyaka nasta’een (You alone we worship, and from You alone we seek assistance) which we recite numerous times a day in our prayers. The statement means: You alone we worship and from You alone we seek succor.  The Prophet, peace be upon him, further explained this while instructing his own young cousin Ibn Abbas: “O My son; I teach you some words of wisdom: Be mindful of Allah, and Allah will mind you. Guard Allah and Allah will guard you. If you ask, ask of Allah alone; if you seek help seek help from Allah. if you ask ask  Allah alone; is you wer to seek help seek help from Allah alone….”

If, however, a person guards against such shirk, there is no harm in using the expression while saying benedictions or sending salawaat and salaam on the Prophet, peace be upon him. Allah orders the faithful to say salawaat; hence we are allowed to say: al-ssalaatu wa al-ssalaamu alaika yaa rasoola Allah; al-ssalaatu wa al-ssalaamu alaika yaa habeeba Allah; al-ssalaatu wa al-ssalaamu alaika yaa khiyarata khalqi Allah

(May Allah’s blessings and peace be upon you O messenger of Allah; may Allah’s blessings and peace be upon you O  the beloved of Allah; may Allah’s blessings and peace be upon you O the best of Allah’s creation).

May Allah implant in our hearts true love for Allah and His chosen Messenger, the seal of Prophets and His beloved, and may He also grant us his intercession on the Day of Judgment-aameen.)