Sleep is God's wise provision for restoring the energy of His creation. All his creatures need to rest, and this is directed by God who has provided the pattern of day and night (see Ecclesiastes 5:12; Psalm 4:8).
In addition to natural sleep, the Bible uses 'sleep' figuratively in two ways:

1. Sleep, as death to be ended by resurrection

Jesus, by the power of God brought Lazarus back from the sleep of death to life: "Our friend Lazarus has fallen asleep; but I am going there to wake him up." (John 11:11; and see Mark 5:39).

We show our faith in Jesus, that he will bring us back to life at the resurrection when he returns, by our 'burial' in baptism and 'raising to life' again. It is also true that we 'die to sin' at baptism and begin 'a new life in Christ' now.

2. Sleep, as inactivity, and indifference to the need to live and work for Christ now

"Wake up, O sleeper, rise from the dead, and Christ will shine on you." (Ephesians 5:14).

God never sleeps: "He who watches over you will not slumber; indeed, He who watches over Israel will neither slumber nor sleep." (Psalm 121:3-4).