Ascension of the LordSince Our Lord's Ascension into Heaven took place 40 days after his Resurrection, we know that it happened on a Thursday, and Ascension Thursday has been a Holy Day of Obligation throughout the whole Catholic world. It is still a Holy Day for much of the world, but in the United States and Canada, many dioceses have transferred the celebration of this feast to Sunday, ostensibly to insure that more people participate in celebrating the day.
I have always thought that eliminating the Holy Day of Obligation waters down the special significance of Christ's Ascension.
The former treatise I made, O Theophilus, of all things which Jesus began to do and to teach, Until the day on which, giving commandments by the Holy Ghost to the apostles whom he had chosen, he was taken up. To whom also he shewed himself alive after his passion, by many proofs, for forty days appearing to them, and speaking of the kingdom of God. And eating together with them, he commanded them, that they should not depart from Jerusalem, but should wait for the promise of the Father, which you have heard (saith he) by my mouth. For John indeed baptized with water, but you shall be baptized with the Holy Ghost, not many days hence.
They therefore who were come together, asked him, saying: Lord, wilt thou at this time restore again the kingdom to Israel? But he said to them: It is not for you to know the times or moments, which the Father hath put in his own power: But you shall receive the power of the Holy Ghost coming upon you, and you shall be witnesses unto me in Jerusalem, and in all Judea, and Samaria, and even to the uttermost part of the earth. And when he had said these things, while they looked on, he was raised up: and a cloud received him out of their sight. And while they were beholding him going up to heaven, behold two men stood by them in white garments.
Who also said: Ye men of Galilee, why stand you looking up to heaven? This Jesus who is taken up from you into heaven, shall so come, as you have seen him going into heaven.