Unless indeed you are disqualified - Disqualified ("reprobates" in the King James Version, Strong's #1384: adókimos) means, according to Vine's, "not standing the test, rejected." It suggests "unacceptable," "disapproved," "unworthy," "spurious," "worthless," "cast away." This word's meaning is illustrated by the following verses:
Titus 1:16: They profess to know God, but in works they deny Him, being abominable, disobedient, and disqualified [adókimoi] for every good work.
Hebrews 6:7-8: For the earth which drinks in the rain that often comes upon it, and bears herbs useful for those by whom it is cultivated, receives blessing from God; but if it bears thorns and briars, it is rejected [adókimos] and near to being cursed, whose end is to be burned.
Being disqualified or rejected is the opposite of having Jesus Christ dwell in us; it is being unfit or unworthy of His presence in us. In other words, a disqualified person is cut off from God! This is the worst possible outcome of a Christian's life: to return to a life of sin and have so much pride that he or she rejects salvation and all that comes with it! God's Word clearly shows that it can happen (see Hebrews 6:4-6; 10:26-31)!
Regular self-examination is a proven way to make sure that it does not happen to us!