it is not wrong, but the better way is to use the singular form. in urdu, plural-forms are used as a mark of respect and singular-forms are generally used for someone far too younger or lower in stature. in persian and urdu poetry, the singular-form is used to address the beloved; and nobody considers this are disrespect either. therefore, in prose nobody refers to RasulAllah sallallahu `alayhi wa sallam in the singular-form whereas the noblest refer to him in poetry as: wah kya jud o karam hai shah e baT'Haa teraa here the 'teraa' (whereas it would be 'aap ka' or 'tumhara' in prose) is used by an admirer referring his beloved. --- those who use the plural forms counter-accuse us that using the singular form is disrespect; whereas we use the singular-form to indicate the tawhid of Allah, that he is Singular and Unique in every aspect. of course, those who use the plural-form acknowledge this in meaning, but we try to choose words such that they indicate that He is One. ---- in english we do not have this form of speech - using a plural-form for respect. in arabic, there are examples but sparely used; and NEVER used when referring to Allah sub'Hanahu wa ta'ala. however, Allah ta'ala has referred to Himself in the plural form in numerous verses. like: verily, it is Us who hath revealed this qur'an; and verily We shall safeguard it. summary: both are right. the later is more approp'right.' wallahu a'alam wa `ilmuhu atam.