The bible describes people as sheep who have wandered away from God. It also tells us that Jesus has taken upon himself the sin of people so that through believing in him he becomes our Saviour.

All we like sheep have gone astray; we have turned-every one-to his own way; and the LORD has laid on him the iniquity of us all. Isaiah 53:6
When people become Christians, Jesus becomes their Good Shepherd who loves them and cares for them.

I am the good shepherd. The good shepherd lays down his life for the sheep. John 10:11

So how do Christians figure out how to live the Christian life? God gives instruction in the Bible for individuals to learn from Him. He also gives instruction for how local churches should function to help the sheep become what God wants them to become, reflections of the Lord Jesus. His plan is to have men who will function as under shepherds who care for the sheep in the local congregation and help them to learn and become more like their great shepherd Jesus Christ. These under shepherds are referred to in the Bible as Elders. It doesn’t necessarily refer to their age but it does refer to their responsibility, desire, spiritual maturity and concern for those Christians in their care.

So I exhort the elders among you, as a fellow elder and a witness of the sufferings of Christ, as well as a partaker in the glory that is going to be revealed: shepherd the flock of God that is among you, exercising oversight, not under compulsion, but willingly, as God would have you; not for shameful gain, but eagerly; not domineering over those in your charge, but being examples to the flock. 1 Peter 5:1-3