A creed is a statement or confession of belief — usually religious belief — or faith. The word comes from the Latin credo for I believe. It is  called symbol (Greek, συμβολον), that means a "token" by which persons of like beliefs might recognize each other.

Christian creeds

It is likely that the earliest creed of Christianity that deserves the title in full is the Apostles' Creed.  The Apostles' Creed seems to have been formulated to resist Gnosticism; it emphasizes the birth, physical death, and bodily Resurrection of Jesus Christ. It reads:

I believe in God, the Father almighty,
creator of heaven and earth.
I believe in Jesus Christ, his only Son, our Lord.
He was conceived by the power of the Holy Spirit
and born of the Virgin Mary.
He suffered under Pontius Pilate,
was crucified, died, and was buried.
He descended into hell.
On the third day he rose again.
He ascended into heaven
and is seated at the right hand of the Father.
He will come again to judge the living and the dead.
I believe in the Holy Spirit,
the holy catholic Church,
the communion of saints,
the forgiveness of sins,
the resurrection of the body,
and the life everlasting.

The Nicene Creed is clearly derived from the Apostles' Creed, and represents an elaboration of its basic themes.  The most important additions to this creed are much more elaborate statements concerning Christology and the Trinity. 
Christians today probably use the Nicene Creed most widely, followed by the Apostles' Creed.

Jewish Creed: the "Shmah"
The Jewish faith recognizes a single creed called the Shmah or Shema Yisrael, a statement of faith in strict unitarian monotheism, the belief in one God. This creed is embodied in a single prayer recited twice a day: "Hear O Israel, the Lord is our God, the Lord is One", also translated as "Hear O Israel, the Lord is our God, the Lord is unique [or alone]."

In Hebrew:  שמע ישראל אדני אלהינו אדני אחד

This is pronounced phonetically in Hebrew: Shema Yisrael Adonai Eloheinu Adonai Echad.

Islamic creeds
The most basic attempt to put the religion of Islam in a brief statement of doctrine is the shahada, the proclamation that there is no god but Allah, and Muhammad is His prophet.

More detailed credal declarations of Islamic dogma constitute aqidah.

The six Sunni articles of belief are:
Belief in God (Allah), the one and only one worthy of all worship (tawhid).
Belief in all the Prophets (nabi) and Messengers (rusul) sent by God.
Belief in the Books (kutub) sent by God (including the Qur'an).
Belief in the Angels (mala'ika).
Belief in the Day of Judgement (qiyama) and in the Resurrection (life after death).
Belief in Predestination (qadar).

Also from the Aqidah of the Salaf is the belief that the faith (i.e. Eemaan) consists of (both) speech and action and that it increases and decreases. This differs from the Murji’ah a sect who uphold the belief of “Irjaa’”-to hold that sins major and minor, do not affect the faith and that faith neither increases nor decreases.

And they uphold the belief that the Quran is the Speech of Allah, His Revelation and Light. It is not created, since the Quran is from Allah and that which is from Allah is not created. One of the attributes of Allah is his Speech. Since His attributes have been with Him eternally, His Speech cannot be created and therefore, the Quran is not created. According to the Salaf, debating about it is disbelief. It is not denied except by a Jahmee. A Jahmee is one who denies Allah’s attributes.

Related pages
 Thirty-Nine Articles
Doctrine

Further reading
 Creeds and Confessions of Faith in the Christian Tradition . Edited by Jaroslav Pelikan and Valerie Hotchkiss. Published by Yale University Press in 2003.

Other websites 
 The Creeds of Christendom - A website linking to many formal Christian declarations of faith.
 www.iclnet.org

Christian genres