Proverbs 4:18 (KJV): "But the path of the just is as the shining light, that shineth more and more unto the perfect day".
As a believer, you are ‘just’ not because you can justify yourself, for all have ‘fallen short of the glory of God’ because of sin. You are ‘just’ because someone justified you, and His name is Jesus. ‘To be justified’ means ‘to be made righteous’, i.e. you are made ‘in right standing’ with God, reconciled to God again.
The word ‘path’ in this verse here means your ‘walk with God’. ‘Shining more and more’ means ‘more and more of the glory of God’ as you walk with God, until the perfect day, i.e. the day God says to you, “Playtime on earth is over! You’ve completed what you needed to do here. You’ve reached your destiny!” and God says, “Now is the time I’m bringing you to a better ‘playground’, a perfect one, one with the fullness of joy!”.
As a cross reference, Isaiah 60:1-2 says ‘Arise, shine; for your light has come! And the glory of the Lord is risen upon you. For behold, the darkness shall cover the earth, and deep darkness the people; but the Lord will arise over you, and His glory will be seen upon you’.
Notice the word ‘but’ both in Proverbs 4:18 and Isaiah 60:2. In spite of the ‘darkness’ and ‘wickedness’ that surround us in this end-time, God says ‘your light will shine’, and Proverbs 4:18 says ‘even brighter and brighter’! People of God, you are living in such a time now! Step into it! In spite of what you see in the world, or despite what people may say, God says ‘you are not diminishing, but you are increasing’! And you know what it means? You’ll be healthier and healthier, wealthier and wealthier, stronger and stronger day by day, not the opposite! Your marriage life, your business, your career, or your ministry will not diminish, but increase, all the way till that 'perfect day'! That’s what God says you are, ‘shining’ brighter and brighter each day! Will you believe for it?
In Psalm 105:37, the Bible says “there is none feeble (weak) in God’s family”, and in Psalm 103:5, it says “your youth is renewed like the eagle’s”. Eagles are strong creatures. They shed old and worn-out feathers and get renewed with new feathers, and that’s how they keep their speed and efficiency! God's Word says you too are being renewed like the eagle! Imagine people coming to you and say, “Hey, you look younger than ever!”, or “Your age betrays your look!” This is happening, because the glory (‘shining light’) of the Lord has risen upon you! Will you believe and receive this too?
God is definitely a ‘youthful’ God. He is as 'energetic' as ever, and He still does new things today. And just because people get old, wrinkled, bended, and die with a ‘walking stick’, it doesn’t mean heaven is full of such! And man, you’ll have a new body, an immortal one! And it’s going to be a youthful one; one that shines like the sun at full strength! Hallelujah!
And the good news is you can have a taste of 'heaven' even right now, yes, here on earth!