The Quran

ما كانَ لِبَشَرٍ أَن يُؤتِيَهُ اللَّهُ الكِتابَ وَالحُكمَ وَالنُّبُوَّةَ ثُمَّ يَقولَ لِلنّاسِ كونوا عِبادًا لي مِن دونِ اللَّهِ وَلٰكِن كونوا رَبّانِيّينَ بِما كُنتُم تُعَلِّمونَ الكِتابَ وَبِما كُنتُم تَدرُسونَ

Muhammad Asad

It is not conceivable that a human being unto whom God had granted revelation, and sound judgment, and prophethood, should thereafter have said unto people,¹ "Worship me beside God"; but rather [did he exhort them], "Become men of God² by spreading the knowledge of the divine writ, and by your own deep study [thereof]."

This obvious reference to Jesus reads, literally, "It is not [possible] for a human being that God should grant him... and that thereafter he should say ...". Zamakhshari regards the term hukm ("judgment" or "sound judgment") occurring in the above sentence as synonymous, in this context, with hikmah ("wisdom").
According to Sibawayh (as quoted by Razi), a rabbani is "one who devotes himself exclusively to the endeavour to know the Sustainer (ar-rabb) and to obey Him": a connotation fairly close to the English expression "a man of God".