I read these prayers of David Livingstone, the missionary to Africa, recently and loved them:
"Lord, send me anywhere, only go with me. Lay any burden on me, only sustain me. Sever any ties but the ties that bind me to your service and to your heart."
"My Jesus, my King, my life, my all, I again consecrate my life to You. I shall place no value in anything I possess, except as it relates to Your kingdom and to your service."