Written by Patrick Doyle, sung by Placido Domingo, from Kenneth Branagh's production of Hamlet. It is based on (with certain derivations) the Latin text of the Book of Wisdom 3:1-3

In Pace

Diligite justitiam, o judices terrae.
Justorum animae in manu Dei sunt, et non tanget illos tormentum.
Visi sunt oculis insapientium mori, et aestimata est afflictio exitus illorum---illi autem sunt in pace.
Tyrannus impius non habet spem: et si quidem longae vitae erit, in nihilum computabitur.
Princeps autem justus, ille in pace est.

In Peace

Cherish righteousness, o judges of the earth
The souls of the righteous are in the hand of God, and the torment (of death) will not touch them.
In the sight of the unwise they seemed to die, and their departure is taken for misery-- but they are at peace.
The ungodly ruler has no hope, and even if he lives long, he shall be regarded as nothing.

Text of Latin Vulgate, Wisdom 3:1-3

Iustorum autem animae in manu Dei sunt et non tanget illos tormentum mortis
visi sunt in oculis insipientium mori et aestimata est adflictio exitus illorum
et quod a nobis est iter exterminii illi autem sunt in pace

Translation of Latin Vulgate (Douay-Rheims)

But the souls of the just are in the hand of God, and the torment of death shall not touch them.
In the sight of the unwise they seemed to die: and their departure was taken for misery:
And their going away from us, for utter destruction: but they are in peace

As you can see, there is a considerable difference between the Latin text of In Pace and the actual Latin Vulgate of the Book of Wisdom. Certain words have been omitted, and the first and last verses are not found in the Bible.