Was Jesus in the grave for 3 days.

Mt 12:40 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.

Lets do a proper interpretation on this:

Jesus rose early Sunday morning. Remember that the night precedes the day in Hebrew reckoning.

Counting backward:

3rd night Sunday night - in the grave

3rd day Saturday day - in the grave

2nd night Saturday night - in the grave

2nd day Friday day - put in the grave just before sunset.

1st night Friday night -Last supper, Gethsemane and illegal trials

1st day Thursday day - Judas betrays Jesus by arranging to turn him in

Since he was not put into the grave until the end of Friday day, "the heart of the earth" does not refer to the grave.

Jer 17:9 The heart [is] deceitful above all [things], and desperately wicked: who can know it?

The betrayal of Jesus placed him in the evil heart of the earth/world. His tribulation began knowing that Judas had already chosen to betray him, and continued through his beatings, trials and death.