The situation of becoming a Christian is like the choices of a child born-into a loving family

Jesus Christ offers us the gift of salvation... It is up to us to accept this gift. But, somehow, the gift is only really accepted when we love Jesus. How can this be understood?
It is like a child born into an ideal loving family. 
The parental love is there, as a kind of background reality; and that parental love brings with it all kinds of benefits. What is at issue here is the child's choices in relation to that parental love. 

Jesus's love for us, and the gift of salvation, is a background reality. What is at issue is our response to this reality. 
Somehow or another (and it doesn't really matter how) we become aware of the nature and possibility of salvation. 
What then?

Every child in a (genuinely) loving family must decide whether that love is real - and some children decide it is not, and proceed accordingly. 
It is noticeable that those children who decide their (genuinely loving) parents do not really love them, seem to be children who are themselves rejecting of the significance of love in life. 
The love-rejecting child may be (apparently) himself incapable of love, or may have decided that love should be subordinated to expediency. The un-loving, expedient child may recognize that his parents are indeed loving, but chooses to exploit the situation - to take as many advantages, while avoiding any inconveniences or responsibilities. 
The love-rejecter notices that those who love him will "give him stuff he wants" - and that is the actual basis of his relationship. 
The love-rejecting child aspires to be a successful parasite in relation to his parents. And if the parasite kills the host? No matter - there are plenty of other hosts; the parasite simply moves-on to the next. 


When it comes to gifts; the love-rejecting child aims to "take the best offer" in any particular circumstance. His allegiance is contingent on his estimate of consequent rewards and punishments. 
He is analogous to a love-rejecter who chooses to accept Jesus's gift of salvation - but someone who does not love Jesus. 
The love-rejecting "Christian" regards salvation as a transaction - either a "free gift", without conditions, or else as an offer with conditions that can be "gamed" in a way that yields net-benefit to the parasite.

The love-rejecting "Christian" is half-right; in that salvation is a kind of free gift; but in the same sense that to be born into a loving family is a free gift - and it is striking how many children (often in adolescence, or young adulthood) reject exactly that free gift. 

The plain fact is that it is impossible to participate in loving family life, and also simultaneously to reject love and exploit family love in an expedient fashion. 
(At any particular moment) If you are not in, then you are out. Insofar as family life is a transaction, then it is not a loving-relationship. 
Because we are mixed and mortal beings, in an entropic and evil world; we can (and do) alternate in our behaviour between the Goodness of loving, and the evil of regarding those who love us in an expedient fashion.
In this mortal life, nobody is wholly and under all circumstances affiliated to God and divine creation. We are all "sinners" as Jesus made clear - and it is as sinners we are saved... or not. 
What is at issue is the aspiration of sinners: what do sinners most want for themselves and from themselves and forever? Is it love?

The thing is: salvation is resurrection to eternal Heavenly life: which is a life wholly rooted in love. And forever. And irreversibly. 
Salvation entails the free and voluntary agreement to leave-behind everything of-us that is not harmonious with love. In resurrection we are re-made and transformed into beings-wholly-motivated-by-love. 
But only if we want this, only if we agree to this - and we need to ask: Why would someone want and agree to this?

Salvation therefore entails an everlasting commitment to live forever in a situation of love: salvation offers this choice, and makes the choice a real possibility. 
And how we have-been in mortal life, what we aspire to as our highest values and hopes - these impinge on that (potentially) final choice. 
When confronted by the choice of salvation: either we value love primarily, or not (and instead value... something else). 
When it comes to love there ultimately is no possibility of trickery, or deception; or rather, rejecting love and adopting the aspirations of a parasite is its own consequence. 

It is simply incoherent to suppose that it is possible freely to choose to reject love as primary here-and-now and because other things are valued more; on the expectation that we will later-on make an eternal and irrevocable choice to live only by love! 
The problem is not that repentance is forbidden, but that people don't want it! 
Repentance is always a possibility, and requires nothing more than to acknowledge and reject some evil, something opposed to God and divine creation. 
Yet people are (to all appearances) very strongly resistant to repenting sin; and very much inclined to assert that their sins are virtues, or insignificant, or that their sins are (somehow) out-voted by their virtues!

How can someone agree to leave-behind their sins - completely and eternally; when they have decided that these sins are actually virtues?  
How can someone agree to live by love - completely and eternally - when he regards love as a means to some other end; when he uses the love of others love expediently. 
And not by lapsing from his ideals, but does this rejection as a matter of principle? 

In the end; I think we can see that accepting the gift of salvation and becoming a Christian is something that cannot be extricated from the primacy of love. 
That - in the end and ultimately - the gift of salvation will not be accepted without us loving Jesus Christ. 
Loving Jesus is not an imposed condition - Not a matter of "you Must Love Jesus or else salvation will be denied you... 

The gift of salvation is not a transaction - it is a relationship; closely analogous to the gift of parental love in an ideal family. 
A love-rejecting child can expediently accept some of the consequences of love; he can exploit his loving family like a parasite exploits its host - but such a child is not, and never can be, a member of a loving family. 
Someone who is motivated to accept Jesus Christ's gift of salvation, but without loving Jesus Christ; will not want, and will therefore reject the complete-and-everlasting state of love that is salvation when the final choice comes to be made. 

(And that is why Jesus places such an emphasis on love, in the Fourth Gospel.)

Note added: Of course, the life-long love-rejecter might nonetheless change his mind, and accept salvation on the basis of wishing to remade from whatever-there-is-of-love in-himself. I believe that the steady background reality of parental love (including from "beyond the grave" can be a factor in this kind of last minute, and perhaps post-mortal, repentance. Because that parental love is always there; anyone who repents, and decides to make love his ideal, can then immediately participate in loving relationships. A love-rejecter may nonetheless be aware that this parental love is still present; and at some point, something may change his mind about the value of this love. So we can never rule out ultimate hope, because that hope may be operative after death. And even "one sided" love may have value in salvation. Yet in the end salvation is always and necessarily by an individual's choice and consent.