and according to Matthew 28:1-4, it says that just before dawn, a gleaming presence of an angel of the Lord suddenly appeared to the keepers (Roman or Jewish Temple? guards). The account goes on to relate how the guards came to the chief priests and wereassured that if they accepted a large bribe to not tell what really happened, the priests would defend them against Roman punishmet for sleeping on guard duty. (See Matthew 28:11-15.) 11  "Now when they were going, behold, some of the watch came into the city, and shewed unto the chief priests all the things that were done.
12  And when they were assembled with the elders, and had taken counsel, they gave large money unto the soldiers,
13  Saying, Say ye, His disciples came by night, and stole him away while we slept.
14  And if this come to the governor's ears, we will persuade him, and secure you.
15  So they took the money, and did as they were taught: and this saying is commonly reported among the Jews until this day. "

The reason for indicating an uncertainty about whose guards were at the tomb, we need to read Matthew 27:63-66 where we see that Pilate, the Roman governor says in verse 65, that the priests "have a watch" and tells them to go their way and set their watch. Based on what is known of Roman law, it would not seem likely that Roman soldiers would be placed under the direction or command of leaders of an enslaved nation nor that nation's religion.  Yet we see the priests "So they went, andmade the sepulchre sure, sealing the stone and setting a watch." (v.66). 

We often hear about the dire consequences if a Roman soldier slept while on guard duty, and yet most preachers and teachers seem to think the Jewish priests had enough power to prevent Roman law from punishing Romans for breaking Roman law. This has to be a stretch of the imagination. The guards of the watch must have been Jewish Temple Guards detached to this special assignment. There obviously had to be temple guards, since there was a great deal 

To understand the importance of when Jesus was crucified and when He arose from the grave, we need to take serious note of His word to the Pharisees: 
Matthew 12:38  Then certain of the scribes and of the Pharisees answered, saying, Master, we would see a sign from thee.
39  But he answered and said unto them, An evil and adulterous generation seeketh after a sign; and there shall no sign be given to it, but the sign of the prophet Jonas:40  For as Jonas was three days and three nights in the whale's belly; so shall the Son of man be three days and three nights in the heart of the earth.
41  The men of Nineveh shall rise in judgment with this generation, and shall condemn it: because they repented at the preaching of Jonas; and, behold, a greater than Jonas is here.
42  The queen of the south shall rise up in the judgment with this generation, and shall condemn it: for she came from the uttermost parts of the earth to hear the wisdom of Solomon; and, behold, a greater than Solomon is here." and in Chapter 16, still in Matthew, apparently on a second occasion, Jesus declares: "1  The Pharisees also with the Sadducees came, and tempting desired him that he would shew them a sign from heaven.
2  He answered and said unto them, When it is evening, ye say, It will be fair weather: for the sky is red.
3  And in the morning, It will be foul weather to day: for the sky is red and lowering. O ye hypocrites, ye can discern the face of the sky; but can ye not discern the signs of the times?
 

Jerusalem until His Resurrection as our new Christian "Holy Week" but then where does the "Lenten" season come into it? The Jews and earlier Israelites abstained from anything with "leaven" in it during the week following the passover, not preceeding it.

The whole point, or points I am making or attemptine go make here is that we need to look at what the Bible really does say and teach rather than what tradition or dear old Pastor Jones or the learned Dr. Stephens says or said about it. True, we do need the definitions of words and the understanding of Bible days customs and sometimes we must rely on such men, but if a clear and definite scripture directly contradicts the supposed fact taught by our more recent "expert," we need to go back to the Bible. If we truly study God's word, nearly every one of these points will be explained somewhere. "My people are destroyed for lack of knowledge: because thou has rejected knowledge, I will also reject thee...." (Hosea 4:6). We need to be like the Bereans in Acts 17:10,11 and study whether these things be so, and to obey the Apostle Paul's exhortation to Timothy to Study to show thyself approved unto God, a workman needing not to be ashamed, rightly dividing the word of truth." (2 Timothy 2:15).

Yes, it is important when Jesus died and when He arose again because to put any length of time on that period is to say He is not true to His word which is blasphemy. 

The Friday teaching began with a religious leader who said if it was the day before the Sabbath, obviously, it had to be Friday, either  forgetting the three days and nights prophecies or intentionally pointing people into unbelief.