"Christianity is a Relationship, not a Religion."
This is often used in Christian circles, while its intent is a noble one - but it can be misleading. What this saying is trying convey is that Christianity is more than just a bunch of "dos" and "don'ts", and following Jesus is not strictly bound up in rules and regulations. In essence it is more like having "a relationship" and not joining "a religion." Herein lies the problem: the relationship and religion aspect are not at odds: it is not one without being the other. Instead, it is more like two different sides of the same coin.
You cannot quite say that Christianity is not a religion... because it is! You cannot deny that it is also a relationship: because we are dealing with a LIVING being: a Being that speaks, acts, has feelings, desires etc. Relationship, not just religion, actually have "rules" as well. Think about this: any romantic or plutonic relationships are based on mutual exchanges. This means that while in a relationship with someone, you have to take into consideration what actually pleases and displeases the other person. It is not all about our own preferences: you cannot want the benefits yet deny its implications.
There are many benefits of being in a romantic relationship, but the implication is we cannot do whatever we want. We cannot flirt with other people, we have to be somewhat accountable about our whereabouts, we have to be transparent with our partners. You cannot say "I want the companionship, but I still want the freedom to do whatever I want." Similarly, if you are friends with someone you will not intentionally keep doing something that makes them unhappy thinking that it is fine because after all it is a "relationship."
We are not responsible for how much God loves us, but we are in charge with how well please He is with us. God is not just our Santa Claus or fairy god mother (or worse, our ATM machine) where we only go to Him and expect Him to do whatever we want. A genuine relationship with God will not just seek the WORKS of God, but actually want to follow the WAYS of God as well. Loving God means obeying what He says (John 14:15, 23).
Loving God also means living the way Jesus wants, not doing whatever we want. God does not just want us to be happy, He actually wants us to be Holy. That is what the bible says! The bible actually has clear instruction on how we should live as Christians, and we would do well to be aware of that what that truly means. Read 1 Peter 1:13-25 and Ephesians 4:17-5:20. A real disciple on a true journey following Jesus does not need to have it all together - but must be willing to surrender it all. Jesus is either Lord of all, or not Lord at all.
Some would contend: wait a minute! Is God not a God of Grace and Mercy? Has He not forgiven all our sins? Does not the Bible say that as long as we believe in our heart and confess with our mouths we are saved? (Romans 10:9) Yes that is all true, but read that scripture clearly: "we believe in our heart that Jesus was raised from the dead but we declare that Jesus is Lord." Declaring is not just paying lip-service, it is actually truly doing it. As they say - actions speak louder than words and you have to walk the talk.
Right believing leads to right living. Whenever a loving parent makes a decision for a child, he does it for the good of that child. There are times when a parent will give the child while he wants, there are times he will withhold. Sometimes he will comfort, other times he will discipline. Sometimes he will give liberty, but other times he sets boundaries. The parent knows why he is doing what he does, but the child has to believe that the parent knows better and has a heart to bless and not curse - and this in turns cause the child to live willingly by the parent's guidance.
We have to realise that we are limited in our own understanding, and how our sinful nature sometimes gets the better of us. We have to trust that God whose ways are higher than our ways, is more than just a mystical being who is aloof - He is in fact more like a personal parent who desires us to grow, mature and experience true blessing and fulfilment.
As Christians, we have to truly follow Jesus - and that means actually heeding the entire Bible, and not just the parts that we like. When you have truly experienced the transforming power and love of God in your life, I am confident that is enough motivation to want to follow Jesus wholeheartedly. A genuine relationship with Jesus will cause us to realise that His commandments are not a burden (1 John 5:2-3) but rather a pathway to a rewarding and fulfilling relationship with an Almighty God.
If you struggle to accept or understand this, I would suggest you first examine yourself (2 Corinthians 13:5) - have you really embraced the Gospel in your life? Or maybe you need to open your heart and sincerely pray: "God, I want to truly know you, and not just know about you - reveal yourself to me." (Hebrews 11:6)