This is a rather silly question, when you think about it. He certainly "observed" His own Resurrection, if that's what you mean! But, no, He did not observe Easter (or the anniversary of His resurrection) while He lived here on earth for the simple reason that He was no longer here as a walking, talking God/Man after His ascension! That, you will recall, was only 40 days after His resurrection, and therefore missed reaching even the first anniversary of His resurrection by 325 days.
2. Did the Lord specify which days are holy and which days to observe?
No, He did not. Neither did He prohibit observations of the days commemorating His birth, death and resurrection, which the Church established very early on.
3. Did the traditional church stop observing these days and substitute their own?
Yes, they did. Certainly St. Paul implies, in Romans 14, that the holy days of the Jews were no longer mandated in the New Covenant. There is absolutely no evidence that the universal Church celebrated even one of them after the destruction of the Temple in Jerusalem, and even the ethnic Jews who were Christians had become absorbed into the general Christian population and stopped their observances by the mid-second Century. To resuscitate these Old Covenant holy days, and imply they have some mandate to this day, bespeaks a special kind of arrogance, and implies a very poor reliance on the the providential care of God for His own Church.
Herbert W. Armstrong, among others, had just such that kind of a lack of understanding of God's Providence. The groups that splintered off from his Worldwide Church of God, such as the one which published this article, continue in that fundamental lack of understanding. Furthermore, their use of such highly discredited sources about "Catholicism" like Alexander Hislop betrays an ignorance of even the most basic understanding of Church and world history, the development of world religions, and a methodology for the cultivation of even the most elementary logic about pretty much anything.
The article heading this thread is ludicrous at all levels. I would not trust its authoritativeness on even a single point. Dig deeper.
DKC>2. Did the Lord specify which days are holy and which days to observe?
M> No, He did not.
You have been blinded to the Holy Word of Elohim by the TraditionsInteresting, You deny that Jesus (Yah'shua) the pre-existent one;
shalom b'SHEM Yah'shua HaMashiach Adonai
One with the Godhead with YHvH; The "Word of God" did not in His Holy Word
tell us starting in Genesis what day He considered Holy.
begun at the Council of Nicea by the Pagan Emperor: Constantine.
So the answer is "no", Christ did not observe Easter. And none of his disciples observed a day dedicated to his resurrection whether it was called Easter or something else. As followers of Christ, Christians, we are to do the same:
1Jn 2:6 He that saith he abideth in him ought himself also so to walk, even as he walked.
1Co 11:1 Be ye followers of me, even as I also am of Christ.
2. Did the Lord specify which days are holy and which days to observe?
No, He did not. Neither did He prohibit observations of the days commemorating His birth, death and resurrection, which the Church established very early on.
Yes, he did. Beginning in Genesis:
Gen 2:2 And on the seventh day God ended his work which he had made; and he rested on the seventh day from all his work which he had made.
Gen 2:3 And God blessed the seventh day, and sanctified it: because that in it he had rested from all his work which God created and made.
The sabbath day was the very first thing made holy in our universe.
Lev 23:1 And the LORD spoke unto Moses, saying,
Lev 23:2 Speak unto the children of Israel, and say unto them, Concerning the feasts of the LORD, which ye shall proclaim to be holy convocations, even these are my feasts.
The Lord, Christ, then goes on to enumerate exactly what days we are to hold holy and which days to observe.
3. Did the traditional church stop observing these days and substitute their own?
Yes, they did. Certainly St. Paul implies, in Romans 14, that the holy days of the Jews were no longer mandated in the New Covenant.
The traditional church did stop observing the holy days given by the Lord. But Paul didn't imply that all in Romans 14. I understand that you read it that way, but can you tell me why?