One reason people fail to believe (in God’s unconditional love) is because they long for the approval and honor of others instead of seeking the approval and honor of God.

John 5:41-44 (NLT)
41 “Your approval means nothing to me,
42 Because I know you don’t have God’s love within you.
43 For I have come to you in my Father’s name, and you have rejected me.  Yet if others come in their own name, you gladly welcome them.
44 No wonder you can’t believe!  For you gladly honor each other, but you don’t care about the honor that comes from the one who alone is God.”

The key to believing (in God’s unconditional love) is to embrace what God thinks about you, not what others think about you – how God relates to you, not how people relate to you.  Most people, including many Christians, place way too much emphasis on what other people think about them and not enough emphasis on what God thinks about them.

People relate to us conditionally, but God relates to us unconditionally because of Jesus.  The tendency (because we deal with people every day) is to want God to relate to us conditionally – just like people do – on a performance-reward basis.  The problem with that attitude is that it prevents us from believing God, and subsequently, it prevents the Gospel from working in our lives.  The key to believing is to base your worth and value on what God thinks about you, not on what people think about you.

One of the reasons life involves so much heartache is because we have such a craving to be loved and appreciated that sometimes we will go to almost any lengths to feel that love and appreciation.  This is one of the reasons sexual immorality is so rampant in our culture today.  We crave the feeling of love and appreciation so bad that sometimes we will do almost anything to get it.  Unfortunately, when we rely on getting it solely from people, sometimes this leads to being in the wrong place at the wrong time doing the wrong thing, and now we are suffering the consequences of those poor choices and wrong decisions – all because we didn’t learn to believe in God’s unconditional love for us.  Every believer must learn how to receive God’s love personally in their heart.

Jesus reinforced this truth (in John 5:42), when He said: “I know that you do not have the love of God in your hearts.”  The phrase, “in your hearts” means God’s love for you is more important than what people think about you, it means God’s opinion of you means more than the opinions of other people, and it means peer pressure will always be filtered through the lens of who you are in Christ.  When someone receives God’s love personally, they are not going to succumb to the pressure that comes from people who manipulate their emotions.