Rockland residents are this week leaving to participate in the hajj, the sacred annual journey to Mecca that is one of the five pillars of Islam.

The hajj, which begins on Tuesday this year, consists of a series of detailed rituals that Muslims believe date back to the prophet Abraham, the patriarch of Judaism, Christianity and Islam, and to the prophet Muhammad, Islam’s final and revered prophet.

Pilgrims believe participation cleanses them of their sins. Millions will go to Medina, the site of Muhammad’s grave, then to Jeddah, and Mecca and nearby Mina and Arafat.

In Mecca, the pilgrims — all dressed in white — will walk and pray the required seven times around the Ka’aba, which is a stone building at Mecca’s Great Mosque and which Muslims believe was built by Abraham and his son Ishmael.

The journey around the Saudi Arabia sites is physically arduous and financially costly, but pilgrims say it is worth it to retrace the steps of their prophets.

The pilgrimage to Mecca is required at least once of all able-bodied Muslims who have the financial means.

The end of the pilgrimage is marked with a joyous, three-day festival known as Eid al-Adha.

The start of three-day festival is one of Islam’s holiest days and commemorates the prophet Abraham’s willingness to give his son’s life as a sacrifice. God stopped him and allowed him to sacrifice a ram instead.

According to the Islamic Society of North America, Eid al-Adha will be on Wednesday.

Gami Mostafa, acting imam of the Islamic Center of Rockland, said the concept of the hajj pilgrimage is one of peace.

“The pilgrimage is a devotion (of) love, obedience, sincerity and submission to God by pilgrims,� Mostafa said. “(The) Pilgrimage has been described as (the) experience of a lifetime and a journey of the soul.�