Oftentimes you will hear the point made that God's forgiveness is conditioned upon repentance, that God does not forgive without prior repentance made on the part of the sinner, and so on. This point seems more compelling at first hearing than it actually is.
Consider, for instance, what the Isaian prophet says in Isa 57:
It shall be said,
‘Build up, build up, prepare the way,
remove every obstruction from my people’s way.’
For thus says the high and lofty one
who inhabits eternity, whose name is Holy:
I dwell in the high and holy place,
and also with those who are contrite and humble in spirit,
to revive the spirit of the humble,
and to revive the heart of the contrite.
For I will not continually accuse,
nor will I always be angry;
for then the spirits would grow faint before me,
even the souls that I have made.
Because of their wicked covetousness I was angry;
I struck them, I hid and was angry;
but they kept turning back to their own ways.
I have seen their ways, but I will heal them;
I will lead them and repay them with comfort,
creating for their mourners the fruit of the lips.
Peace, peace, to the far and the near, says the Lord;
and I will heal them (Isa 57.14-19).
The prophet here is referring to the return of Israel from exile in Babylon. After relating at length the debauchery of the Israelites in exile (57.1-10), the prophet assures them that, though they have sinned in these grave ways, though they kept returning to their own ways, yet the LORD will heal them. He will bring peace and he promises a return from exile. From the fact that the prophet insists that the people continue in sin and yet God will heal them anyway, we infer that this deliverance is an unconditional one. It is God's act of grace for his people who seem unable to obey him in a way he wants.
The same point is made in the New Testament, of course, when Paul says that while we were still sinners, Christ died for us (Rom 5.8). The death for our sins occurs not after we repent and believe, but while we are still sinners. Consequently it is an unconditional act of grace. Faith and repentance do not win for us forgiveness and grace, but are the ways in which we accept the grace given and recognize what God has already done for us in Christ.