You owe no assailant a thorough explanation of your beliefs. Most of your critics could not provide a cohesive theological explanation of their beliefs beyond, "There's a verse in the Bible that says..." Second, they are not in conversation with you to be convinced of anything themselves. It is not a true dialogue. They are not thinking. They are simply protecting their ideas, dogma, and personal fears from the intrusion of grace. Sadly, people who fail to offer grace have rarely allowed themselves to enjoy the full measure of grace afforded them. In the end they are trying to condemn or convince you. So use these arguments if you wish, or simply hold them close and sing with confidence, "Jesus loves me; this I know. For the Bible tells me so."