When we are born again, we have spiritual senses. God speaks to us and directs us. When we accept His direction and yield to the Spirit of God, we become more mature. Our spiritual senses are exercised by reason of use. When we fall short of that and do what our own soul wants to do, then our consciences are seared as with a hot iron (1 Timothy 4:1-2). (some caveats about hearing God's Voice)

Hebrews 5:13 For every one that useth milk is unskillfull in the word of righteousness: for he is a babe.

Hebrews 5:14 But strong meat belongeth to them that areof full age,even those whoby reason of use have their senses exercised to discern both good and evil.