"What shall we say then? Are we to continue in sin so that grace may increase? May it never be! How shall we who died to sin still live (wallow) in it?" A great mentor of mine wrote those words.
This is heartening. So, you make a conscious act of the will to avoid sin - or at the very least to sin less frequently or less grievously - with God's help.
Because this is right. This is the way to go. But it is not Predestination. When we consciously try to avoid sin, we choose. We make an act of the will. We practically do nothing else - God does all the work - but we decide to change. Or we don't. God does not choose for us.
Now listen! Today I am giving you a choice between life and death, between prosperity and disaster
This is the way we engage with God. He makes it very simple and the choices could not be more stark and obvious. But it is up to us. We can indeed finally reject Him.