Also called Whit SundayPentecost Also called Whit Sunday. Seventh Sunday after Easter. The Jewish Feast of Weeks (harvest). Day when the Holy Spirit descended upon the disciples (Acts 2).. Seventh SundaySunday Observed by Christians as a day of rest and worship. Traditionally regarded as the first day of the week, the day on which Christ's Resurrection is believed to have taken place. For this reason it replaced the Jewish Sabbath in Christian practice. after Easter. The Jewish FeastFeast Special liturgical celebration to commemorate an event or saint. of Weeks (harvest). Day when the Holy SpiritHoly Spirit Or 'Holy Ghost'. Third person of the Trinity. descended upon the disciples (Acts 2).