Though Prophet Muhammad used to offer prayers while facing Jerusalem in Mecca, he would also face the Ka`bah in the same direction as Jerusalem. However, when he immigrated to Medina, he could no longer face the Ka`bah and Jerusalem at the same time, which aggravated Prophet Muhammad’s feelings of sadness, pain, and agony driven by homesickness and estrangement.
Jumu`ah or Friday is so important in Islam. It is considered the best day of the week for Muslims. It is the day where the Muslims gather to offer prayer in congregation. The day of Jumu`ah is one of the blessings that the Muslim nation has been endowed with. Imam Ibn Kathir said, "It was named Jumu`ah because it is derived from the word Al-Jam` in Arabic which means to gather, as Muslims gather on this day every week, and Allah has commanded the believers to gather for His worship.
THE MUSLIM PRAYER BOOK - RULES - CONCEPTS & MERITS