In the New Testament alone, the phrase "one another" is used roughly 100 times, and 59 of those specifically reference our relationship with the body of Christ—59 times! Hypothetically, if we were to spread out the "one another" passages evenly throughout the New Testament and read five chapters a day during our devotional time, we would encounter one of these passages every single day! It seems clear that how we live in community within a local body of Christ is important. To put it in perspective, we are commanded 59 times to take action in our service to one another in Christ.
One helpful thing to notice in these 59 passages is that there is nothing qualitative about the other person when it comes to the church. Perhaps the reason for this is that our love for one another is not based on anyone's merit, but rather on the merit of Christ. It is the gospel alone that leads us naturally to a supernatural affection for the body of Christ. When the gospel has been truly believed, it will always lead us to love God's people. This is one of the very marks of spiritual rebirth in 1 John: "Beloved, let us love one another, for love is from God, and whoever loves has been born of God and knows God. Anyone who does not love does not know God, because God is love. If anyone says, 'I love God,' and hates his brother, he is a liar; for he who does not love his brother whom he has seen cannot love God whom he has not seen. And this commandment we have from him: whoever loves God must also love his brother" (1 John 4:7-8; 20-21).
One cannot love God and hate his brother because love for the brethren is a natural and necessary byproduct of our love for God. When we truly understand the extent to which we have been forgiven in Christ, we can't help but want to extend that forgiveness and love to those around us—specifically, the body of Christ. The way we love others is not so much dependent on how well we know them, but on how well we know God. As we grow in our knowledge and understanding of the gospel, it compels us to love our brothers and sisters. If you want to grow in your love for the people around you, it begins and ends with wholeheartedly seeking after Christ.