Why do Muslims face Mecca in prayer?

Muslims face the Ka'ba in Mecca when they pray. The first direction of prayer was toward Jerusalem, before it was changed to the Ka'ba.

Muslims face the Ka'ba in the Sacred Mosque in Mecca when they pray. This direction is called the qibla, and it is known in Mecca. Tradition reports that the first qibla was toward Jerusalem, and that it was then changed to the Ka'ba, as the entry Jerusalem sets out. The rules on the qibla in prayer and how to determine it are set out in the entry Prayer.

Details and disagreements are added in the related entries.