Grow up or be childlike?

Ok so we all know that Jesus said we should be childlike. But in Matthew 5.48 we are told to grow up. Is this another one of those contradictions that seem to occur in the Bible that for some people muddy the waters? Lets face it, there are quite a few passages in the Bible that at first glance seem to contradict one another. This though is more a failing on our part, a failing in understanding and false interpretation. Going back to my "example" when we look more closely at the scriptures we find that although Jesus did instruct us to be childlike, it was to be childlike in faith. Jesus wants us to accept him and his truth as a child listens and trusts implicitly in their parents. As a child we should ask questions and explore our faith with vigour and curiosity. However when we receive an answer for Him we should trust it whole heartedly. In Matthew 5.48 we are being instructed on a totally different subject, our interactions with other kingdom subjects and the world. We are being told that it is not enough to be nice and "Christian" when it is easy with people who are easy to deal with. We must be Christlike in all our life, with those who attack us and those who hate us. We must model our whole lives on Jesus' example. Now I know this is a fairly simple and easy comparison to make, but it is the point I am trying to make. Out there are many many people who have at best a little understanding and maybe a small nugget of knowledge about our Lord and Saviour. With these people confusions will arise over such passages. As active, practising Christians it is our duty to know as much as we can about our God and His word. Short version is there is no excuse not to know the Bible, there is no excuse not to do Bible study. At the end of the day our eternal lives depend on our actions here, lets at least try our best.