Perhaps you will raise this one last objection. Of course our motives will always be mixed. And so what if they are. God's love and God's calling are irrevocable. So don't even try.
Love covers a multitude of sins.
That is the awesome and powerful mystery of God's grace. That God calls us in spite of all our imperfections, works through us in spite of our mixed and impure motives, keeps on working through us even when our mixed up attempts at living out God's love go awry. And never, ever, ever, lets us go.