In John Stott’s Radical Disciple, in a chapter on Christlikeness, he cites William Temple:

It’s no good giving me a play like Hamlet or King Lear and telling me to write a play like that. Shakespeare could do it; I can’t.
And it is no good showing me a life like the life of Jesus and telling me to live a life like that. Jesus could do it; I can’t.
But if the genius of Shakespeare could come and live in me, then I could write plays like his.
And if the Spirit of Jesus could come and live in me, then I could live a life like his.

Stott concludes:

God’s purpose is to make us like Christ, and God’s way is to fill us with his Holy Spirit