Casual friends or companions may engage in mutually agreeable activities of interest without much residual connection. Dear friends maintain an interest in personal contact over a wide variety of experiences.
The differences between these two groups (comrades or associates—hetarios and friends—philo) is elaborated and discussed throughout the Bible. Philo, translated as friend, was originally a description of the association such as friendly or dear, however in usage became the relationship itself. One’s friend then denoted a caring, friendly affection of depth beyond the shallow association of comrades.
The sharing of good times and bad, of expressions of health, joys, exasperations and sorrows all make up the stuff of friendship. Agreement on every point of life is not essential, it is the concerns for each other, the enjoyment of sharing and knowing the bonds of acquaintance are long lasting. Trusting in mutual judgments and standards are also important. A friend is someone we treat with special affection.
John tells us of Jesus’ teaching on love and friends where he says “greater love has no one than this to lay down his life for his friends (Jn 15:13). No higher expression of love could ever be given. Life is the most valuable object we possess; and when a man is willing to lay that down for his friends or his country, it shows the utmost extent of love. (from Barnes' Notes).
One cannot be friends with God and the world. James said “…do you not know that friendship with the world is enmity with God?” (Jas 4:4). We must always be careful of who we choose as friends. It is best when friends have a love of God and a desire for righteousness in common. True friends are beyond companions and worshipping together builds a closeness of the same goal of a heavenly home.