Here's a summary of what Cusick told Parade Magazine:
LOST and Spirituality & Love:
"Lost has become bigger than just the little details. It's become a show about themes -- spirituality, how to live your life, what's important in life. But I think at the heart of Lost, what certainly draws my attention, is how love has played a part in all of our lives. You know we had tragedy, with Penny and Desmond and with Isabella. And the finale really focuses on those dynamics. It provides an emotional core -- how love heals and how it hurts and how it can break you."
On the Spiritual Context of LOST:
"The religious context for me came up in Season Two, with the button [that Desmond had to keep pressing to ward off another electromagnetic event]... That was a fascinating metaphor, I think, for religion. [That element has] been there very, very long. It hasn’t just appeared. But it’s not so much religion, it’s more spiritual. It’s more of a spiritual show and I think it’s going to be very strongly spiritual towards the end."
Desmond is a Man on a Mission:
"He’s trying to do something... He’s certainly on a mission, he knows what he’s about. He’s certainly driven and he’s not [asking] the rest of the group, ‘What should we do?’ He’s not trying to figure stuff out – he knows exactly what he’s doing and he has such a strong purpose, he’s very clear about his objectives."
image via ABC