IKhisimusi belingagujwa njalo ngomhlaka-25 Disemba. Ngenkathi iKhisimusi ligubha ukuzalwa kukaJesu Kristu, akukho okukhulunywa ngomhlaka-25 Disemba eBhayibhelini. Iningi lezazi-mlando empeleni zisikisela ukuthi uJesu wazalwa entwasahlobo. Futhi usuku lwakhe lokuzalwa alubanga yiholide elisemthethweni kwaze kwaba yikhulu lesithathu leminyaka. Ezinye izazi-mlando zikholelwa ukuthi usuku empeleni lwakhethwa ngoba luhambisana nomkhosi wamaqaba weSaturnalia, owawudumisa unkulunkulu wezolimo uSaturn ngokugubha nokunikeza izipho.