The disciples must have extended the lease of that upper room in which they ate the Last Supper. They were still there fifty days after the Resurrection, ten days after the Ascension of our Lord. They were fearing for their lives. When the Holy Spirit came on them, they became brave.
The Holy Spirit came on the disciples ten days after our Lord’s Ascension. He told them that they would be his witnesses – and so they were! And so are we! Our task is quite simple: To witness Christ.