What steps would you suggest that he, or anyone else, should take to develop the love for Christ that he is deficient in?
It seems to me that loving someone involves, essentially, a choice to do so, expressed in appropriate actions. Love is a choice to value another person (whether human or God) above myself, and to put the interests of that person ahead of my own.
As with all choices, this requires some incentive. To increase our love for God, we should cultivate those attitudes that provide the necessary incentives to make choices toward that end.
This is why some people think we should preach the most terrifying vision of hell possible—i.e., in order to provide
sufficient incentive for people to choose to love God. However, as has been pointed out earlier, though fear of punishment does indeed provide incentive to obey, it does not provide incentive to love. Punishment appeals only to the self interest, and provides incentive for one to
protect himself from consequences. If one comes to love the person that he/she fears, it will not be because of the fear ("there is no fear in love"), but because of additional considerations that allow him/her to love the punisher
despite the fear of punishment.
Three biblical incentives for love, which do not involve fear, are:
1) Pity for the weak or the vulnerable. This seems to be God's motive implied in John 3:16, and is stated outright in Romans 5:6-8. This is why parents love their children—because of their being vulnerable and in need of our assistance. "Like a father pities his children, so the Lord pities them who fear Him" (Ps.103:13). This is also what motivated the "Good Samaritan" to help a helpless stranger, and motivates us to love the needy (1 John 3:17). When it comes to loving God, this factor may not seem to apply, but God is also emotionally vulnerable (if the scriptural representations of Him are correct), and, as we should feel loath to bring emotional distress to human being, we should be equally unwilling to grieve our Maker, who has given us only good things, or such things as He intends to work for our good.
2) Gratitude. It is a normal human reaction to appreciate the mercy and generosity of others shown to us. Ingratitude, though only too common among us, is a sub-human trait. We love God because He first loved us. Jesus said, "He who is forgiven much, loves much." David wrote, "Bless the Lord, O my soul, and do not forget all HIs benefits" (Psalm 103:2). Those who do not contemplate the undeserved blessings that God has given them are not likely to feel much in the way of love for God. People who think they deserve the good circumstances that they enjoy, or who focus more on the things that they wish they had, but do not have, are spoiled ingrates. This has become an epidemic in our pampered culture, reducing our capacity to love anyone but ourselves.
3) Admiration. We love people whom we admire. Think of our favorite celebrities, athletes, statesmen, etc. Sometimes these people are truly our superiors, and sometimes their mere fame intimidates us. I was once in a cafe in Hollywood and Vince Vaughn was at the next table. I am not even a fan of his, but knowing that he was a famous person made me feel like this was something special. If we regard someone as more amazing than ourselves, we naturally feel privileged to be close to, or included in the circle of, that person. Some children love and admire their parents, not so much out of gratitude for what they provide, but for their perceived superiority in size, strength and knowledge of every subject. Similarly, our contemplating the glory and magnitude of God should produce admiring awe, which inspires deference, and encourages love.
How can anyone know if they love God enough to pass this test?
Biblically, the test of genuine love is the willingness to die for someone. If we are faithful in the face of martyrdom, it is a pretty good indicator that we love God—just as the hero who boldly dies for his country or for his companions is exhibiting love for his country or his companions.
Of course, some may say that they do not know whether they would be faithful in situations that, at present, are entirely hypothetical.How do I know what I would do when threatened with the lions' den?
The beginning of the Christian life is the denial of self, and the accepting of a cross (Matthew 16:24). Those who have never taken that step into Christianity, but have taken lesser steps which they regard to have been the embracing of something they think is Christianity, may very well wonder what they would do in a life-threatening situation. Those who are calculating the risk/benefit ratio of being faithful to God, on a case-by-case basis, might well question whether their analysis would turn up the right numbers in a deadly encounter with a shooter who asks, "Are you a Christian?" Now is definitely the time to consider this, rather than waiting until the crisis arises.
It is a shame that so many people have been encouraged to think of themselves as Christians, who have neglected the very entry-level steps of commitment, so that their choices day-by-day are still being calculated on the question of advantage to themselves. They have not yet "denied themselves"—that is, denied their self-rule and commitment to self-interest. "Christianity," as they have embraced it, is simply another extension of their self-interest. They cannot say, "For me
to live is Christ; and to die is gain."
I can think of two factors in deciding, realistically, if we love Christ enough to die for Him:
1) Do we begrudge the smaller sacrifices that our Christian commitment currently requires of us, day-by-day, or do we take joy in them? People in love take pleasure in blessing their loved ones at their own personal expense;
2) Do I trust that God, who gives me grace for my present trials, will give adequate grace for the ultimate test when (not if) the time comes? Trust in God inevitably brings grace (Rom.5:2; Eph.2:8). Do I love God enough to trust Him with my future—both temporal and eternal?