One of the posters giving offence at a Muslim protest over the Pope's quotation said "Jesus is the slave of Allah". It was obviously designed as an insult and a declaration of the superiority of Islam over Christianity.
However, as I think about it, it exemplifies the superiority of Christianity over Islam as an approach to God.
I doubt that the poster bearer realizes it but the slogan derives from Paul's letter to the Philippians. "... Christ Jesus: who, being in the form of God, thought it not robbery to be equal with God: but made himself of no reputation and took upon him the form of a servant, and was made in the likeness of man." (Ch 2 vv 5-7). The Greek word translated 'servant' is 'doulos' and it should more properly be translated 'slave'. 'Allah' is, of course, simply the Arabic word for God.
It is true. Jesus is the slave of God. He was/is/always will be co-equal with God, but made himself a slave to demonstrate how to approach God.
Mohammed was a Catholic heretic. His new form of religion had a blind spot for humility and took upon itself the arrogance of conquest and subjection. Jesus taught that the first shall be last and the last first. Jesus taught that except you become as a little child you cannot enter the kingdom of heaven. Jesus taught that it is easier for a camel to go through the eye of a needle than a rich man to enter into the kingdom of heaven. Jesus taught that the poor in sprit, and the meek, and the peacemakers, and the merciful, and those who hunger and thirst after righteousness are blessed.