Eph 4:18 having their understanding darkened, being alienated from the life of God, because of the ignorance that is in them, because of the blindness of their heart;
Blindness; Greek, “hardness,” literally, the hardening of the skin so as not to be sensitive to touch. Hence a soul’s callousness to feeling (Mk 3:5). Where there is spiritual “life” (“the life of God”) there is feeling; where there is not, there is “hardness.”
Jamieson, R., Fausset, A. R., & Brown, D. (1997). Commentary Critical and Explanatory on the Whole Bible (Eph 4:18). Oak Harbor, WA: Logos Research Systems, Inc.
A negative mind darkens understanding, so we misunderstand or have any insight into even obvious truth, because we are cut off from connection with God and the inevitable ‘life’ that flows through that connection from Him to us. Ignorance is a refusal to receive knowledge, in this instance because of the lack of ‘sight’ in the heart. We ‘see’ with the heart which is the seat of our trust, love and desires. When we sin we separate ourselves from God. We cannot connect with Him. In this state we look at the Bible and it fails to live for us, whereas when we are clean and close to God every page of the Bible lives. Prayer provides easy access into the presence of God so we feel the anointing and a fountain of joy springing up within. But when we are guilty, our spirit is divorced from our mind and emotions. We are divided within, isolated from ourselves and God. As I said, we know we are in a state of dividedness from God because we feel distant from the Bible. It doesn’t live for us. The division we experience within bleeds into our relationships so we find ourselves at variance with others. When we are at peace within ourselves, we find it easy to be at peace with others and to be peacemakers.