Take the conversion of Augustine. One day when traveling to his home in Milan he heard a child say "Tolle lege, tolle lege" ("Take and read!"). He opened the book that the child gave him to Romans 13:14:
Romans 13:14 14 But put on the Lord Jesus Christ, and make no provision for the flesh in regard to its lusts.
He was converted then. May we be those who are witnesses for Christ today...even if it is merely handing the Scriptures to someone in hopes that the Holy Spirit may do His saving work.