Growth is one of those things that many people want, but nobody wants to work for it. We want to grow but seem to think that we will magically change into the image of Christ.
It is true that we grow in the Lord through grace, but God works through means to help us grow. One of the means is the Word of God. So if we want to grow in "passion" for Christ we must cling to Scripture and speak the Word into other's lives to help them grow. It is by God’s grace that we have the Bible and are able to understand the words therein.
I fear that too many times we put stock into the fleshly deeds that we may do like the Philippian dogs that Paul mentions. Later on in that passage, Paul lists his credentials about what many would think would be honorable. Yet, Paul tells his readers that it is rubbish! He says that it is all rubbish compared to knowing Christ, sharing in his suffering and resurrection, and becoming like him in his death!
There is nothing inherently about us that can get us closer to God. But, by his grace we have his Word and that is the avenue that God speaks to us today. When we spend time with God and spend time with his Word then we have the opportunity to grow!
Think of it on human terms: Since getting married 18 months ago, my wife has changed a little bit. I have a strong and dominant personality and there are certain things that I have done for years that Karissa, my wife, didn't use to do. But, since we spend so much time together, she has picked up some of my traits. Whether it be some small quirks in the way I do things or certain types of humor, she has picked these up from me.
How much more so if we spend time with the strongest and most dominant personality imaginable, God! By God's grace we have his Word. His infallible, inerrant, Word that the Holy Spirit works through to help shape us into the image of Christ and do good works.
God works by grace and by his grace he works through means to accomplish his purposes. One of the means that we grow in godliness is through study and meditation on Scripture and responding to God speaking to us in prayer.