Psalm 36:9 (NKJV)
If you were in a dark place, with very little or no light, and a distance away from you there was some light, would you move towards that light? Normally the answer would be yes, usually we want more light and not less. As you move towards the light you would be able to see things better due to the increase of the light. If you just stayed where you were you would not have any more light than you did at the beginning, and if you moved in the opposite direction you would have less and less light. For most people the simple thing to do when it is dark is to get more light.
God's Word will give us light, it will give us understanding (Psalm 119:130). Psalm 36:9 tells us how in God's light we get more light. The more light and understanding we have from God's Word, the more light and understanding we will be in a position to receive from God's Word. In other words, as we come to better understand what God has said in His Word, we can then receive even more light, wisdom, understanding, and clarity from God's Word. But, when we do not follow, or even reject, the guidance we receive from God's Word it is like turning off the light.
If we do not receive the light and understanding that God's Word can give us, the less we will understand what God is saying to us through His Word. This is the reason some Christians struggle, they have received some light from the Bible but they have ignored, rejected, or failed to act on that light and they have put themselves in the dark. But, no matter where we are today, more light is available to us and God is ready to help us understand and follow His Word. When we walk in the light and understanding of what we know from the Bible it is like bringing more light into our lives.