Every sin is either a subtle or an overt rejection of the love of God. How so? Because God in his love for us has committed himself — and signed it with his own blood — to care for our every need. He insists on it and delights to do it. Hence, when we look to something other than him to meet the need, we are rejecting his loving care for us. That is what sin is and does.
Spiritual maturity, on the other hand, is marked by a growing confidence in God and his loving care.