The Holiness that God demands.

When we decide to follow the path that God has determined for us, we are making the best decision of our lives, but this must be compensated with actions on that path, we arrived as children, without knowing anything, but with the passage of time we must learn and putting into practice what has been learned.

Peter 1
14 as obedient children, do not conform to the desires that you had before being in your ignorance;
15 but, as he who called you is holy, you also be holy in all your manner of living;
16 because it is written: Be holy, because I am holy.

Source

In this biblical passage we see how the apostle Peter teaches us the growth that a Christian should have, we must always live in obedience to God and this will make us change any past attitude that we have had and that has not been in accordance with the will of God.

If we have been called by God and we have accepted his call, we must walk based on it, we must imitate the character and actions of Jesus, which are clearly reflected in his word.
If God is Holy, we must be too, because He Himself with His Holy Spirit will make over in us and will transform us according to how He is. In our strength it may be impossible but with God it is not. Our way of living must be completely new, different from what we have been doing, letting the old man die and allowing God to reign in our being.

When God rules within us then this will surely be reflected on the outside. People will look at the work that God has done in us and they will also look for what we have, action that will lead them to meet God and that their lives can also change.
Let's not settle for continuing to live the same when we have a father who can change our lives, help us discard the bad and live differently under his precepts.