Sheikh `Abd al-`Azîz b. `Abd Allah b. Muhammad Al al-Sheikh, Grand Mufti of Saudi Arabia
The word “Muhammad” is derived from the Arabic root word “hamd” meaning “praise”.
It is the emphatic passive participle of that root and can be translated as “the Oft-Praised One”.
As for Ahmad, is the superlative form of the same root word “hamd”. It means “the Highly Praised One”.
Ahmad is the name Jesus (peace be upon him) mentioned when he foretold of his coming.
Allah says: “And when Jesus son of Mary said: O Children of Israel! Lo! I am the Messenger of Allah unto you, confirming that which was revealed before me in the Torah, and bringing glad tidings of a Messenger who will come after me, whose name will be ‘the Highly Praised One’ (Ahmad).” [Sûrah al-Saff: 6]
The Prophet (peace be upon him) also had the name al-Mutawakkil, meaning “the one who relies on Allah”.
The Prophet informs us that Allah said to him: “…and you are My servant and Messenger and I have named you al-Mutawakkil.” [Sahîh al-Bukhârî]
Allah’s Messenger (peace be upon him) enumerated a number of his names when he said: “I have many names: I am Muhammad. I am Ahmad. I am al-Mâhî (the Obliterator) by whom Allah obliterates disbelief. I am al-Hâshir (the Gatherer) who gathers the people at my feet. I am al-`Aqib (the Successor) whom none comes after.”[Sahîh al-Bukhârî and Sahîh Muslim]
The Companion Abû Mûsâ al-Ash`arî relates the following:
Allah’s Messenger (peace be upon him) called himself by many names, some of which we committed to memory and some of which we did not. He said: “I am Muhammad. I am Ahmad. I am al-Muqaffî (the Sender). I am al-Hâshir. I am the Prophet of Penitence. I am the Prophet of Mercy.” [Sahîh Muslim]
And Allah knows best.
Source: Islam Today