a summon

But the LORD answered me,
Say not, "I am too young."

To whomever I send you, you shall go;
whatever I command you, you shall speak."

Jeremiah one : seven

for His sake

For His sake,
     I have accepted the loss of all things and
            consider them so much rubbish,
                   that I may gain Christ and be found in Him ...

http://hannah.bodenhamer.org/gallery.htm

... not having any righteousness of my own based on the law

but that which comes through faith in Christ. 

Philippians 3: eight B & nine