Have you ever been in a period of life that you were so focused on yourself? Sure, we are selfish by nature, but even after we accept Jesus into our hearts sometimes we still use God & Christianity as a self help and personal/spiritual development. Does God want us to continue to be sanctified? ABSOLUTELY! That's not our mission though - we are called to the Great commission and we are told in Matthew, "to go and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, and teaching them to obey everything I have commanded you. And surely I am with you always, to the very end of the age."
Seventeenth century British missionary Hudson Taylor said it in another way that I couldn't agree with more:
"I used to ask God to help me. Then I asked if I might help Him. I ended up by asking God to do His work through me."
– Hudson Taylor
Ask God to do his work through you, and your sanctification will be the result and His work will be done in and through you.