'Being renewed' here is 'anakainoo' in Greek. It actually means 'being renovated', i.e tearing down the old, and building up the new (likened to having a house renovated). So, 2 Corinthians 4:16 actually means 'your inward man is being renovated day by day'.
Beloved, as you allow yourself to be 'renovated' by the Lord, that's when you grow spiritually. To 'grow spiritually' is to grow to be more & more like Jesus. When you grow in the 'inside' (inner man), or in character (to be more & more like Jesus'), you'll see growth in your outside (i.e your career, business, ministry, etc). In other words, the change in your 'inside' is in direct proportion to the change in your 'outside'!
One such example of 'spiritual growth' can be found in Joseph's life (Genesis 37). Joseph was meant to have a great destiny. However, he needed to be 'renovated' first in the 'inside' before God could use him in a significant way.
In Genesis 37:5-8, Joseph had a dream about his brothers bowing before him. However, it wasn't time yet for it to be fulfilled. So, when he told his brothers about the dream, they ended up hating him more. Even before that, Joseph was known to bring ‘bad report’ and 'gossip' about his brothers to their father. So, instead of being 'promoted' according to the dream, he ended up being sold as slave in Egypt (Genesis 37:36), and life went further downhill when he was imprisoned (Genesis 39:20).
However, through the years, something did change in the 'inside' of Joseph. From a 'gossiper' who brought 'bad report' (Genesis 37:2), he became someone who showed 'care & concern' for others (Genesis 40:6-7). It's a sign of spiritual growth, and this was also the beginning of a change in the 'outside' for Joseph! When the chief butler was thrown into prison for offending the king, Joseph showed him genuine care by asking, "Why do you look so sad today?" It's like saying, "Are you okay? Is there anything I can help you?" This act of kindness did open the chief butler's heart, who had a dream but didn't know its interpretation. So, he shared the dream to Joseph who then helped him interpret. The dream did come to pass as Joseph had interpreted, and the chief butler was restored back to his position by the king (Genesis 40:21).
Two years later, Joseph's moment of 'promotion' came. When the king had a dream and nobody could interpret it, the chief butler remembered Joseph, and he told the king what happened two years ago in the prison (Genesis 41:12), and how Joseph interpreted his dream correctly. Upon hearing that, the king sent for Joseph (Genesis 41:14), and was pleased with Joseph's interpretation & advice (Genesis 41:37). That's how Joseph was 'elevated' to be the prime minister of Egypt, second only to the king!
You see, the change in the 'inside' of Joseph eventually led to the change in his 'outside'. From a slave & prisoner, Joseph rose to become a prime minister, and just as in the dream he received, his brothers did come (to Egypt) bowing before him for food supply in a time of famine! (Genesis 42:6)
