John MacArthur, On the Nature of True Belief

“A true believer is one who signs up for life. The bumper-sticker sentiment ‘Try Jesus’ is a mentality foreign to real discipleship – faith is not an experiment, but a lifelong commitment. It makes taking up the cross daily, giving all for Christ each day. It means no reservations, no uncertainty, no hesitation (Luke 9:59-61). It means nothing is knowingly held back, nothing purposely shielded from His lordship, nothing stubbornly kept from his control. It calls for painful severing of the tie with the world, a sealing of the escape hatches, a ridding oneself of any kid of security to fall back on in case of failure. Genuine believers know they are going ahead with Christ until death. Having put their hand to the plow, they will not look back (Luke 9:62).” (The Gospel According to Jesus)