The texts assigned in the Revised Common Lectionary for Saturday of Holy Week are Job 14:1-14 (affliction, pain, and suffering), Psalm 31:1-4, 15-16 (in your unfailing love, rescue me), 1 Peter 4:1-8 (live not by desires, but by the will of God), and Matthew 27:57-66 (the burial of our Lord Jesus).
The Easter Vigil service is a separate service with a large number of readings. The readings rehearse the story of salvation through the Hebrew Bible as well as the first Easter story. The historical use of the Vigil was a baptismal service for converts that had been prepared over a period of several years for entrance into the church. Apostolic Tradition of Hippolytus (circa 225 AD) gives some details of the event:
They shall all keep vigil all night, reading and instructing them. Those who are to be baptized are not to bring any vessel, only that which each brings for the eucharist. It is indeed proper that each bring the oblation in the same hour. At the hour in which the cock crows, they shall first pray over the water. When they come to the water, the water shall be pure and flowing, that is, the water of a spring or a flowing body of water. Then they shall take off all their clothes. The children shall be baptized first. All of the children who can answer for themselves, let them answer. If there are any children who cannot answer for themselves, let their parents answer for them, or someone else from their family. After this, the men will be baptized. Finally, the women, after they have unbound their hair, and removed their jewelry. No one shall take any foreign object with themselves down into the water.
Even a tree has more hope!
If it is cut down, it will sprout again
and grow new branches.
Though its roots have grown old in the earth
and its stump decays,
at the scent of water it will bud
and sprout again like a new seedling.
Low in the Grave He Lay, stanzas of the hymn text by Robert Lowry (1874):
Low in the grave He lay, Jesus my Savior,
Waiting the coming day, Jesus my Lord!
Vainly they watch His bed, Jesus my Savior;
Vainly they seal the dead, Jesus my Lord!
Death cannot keep its Prey, Jesus my Savior;
He tore the bars away, Jesus my Lord!