1 Thessalonians 5:14
And we urge you, brothers, admonish the idle, encourage the fainthearted, help the weak, be patient with them all.

As he concludes his letter to the church in Thessolonica, and after he has dealt with the manner in which leaders are to be respected, Paul gives additional instruction to the believers on how to treat one another within the body of Christ. In fact, he urges them to do such things, stressing their importance.

First, the call is to admonish the idle. Who are the idle? Those who have not put their faith into action. They know many details about faith, and perhaps are even well-versed in Scripture. Their intentions seem good, but when their lives are examined, they have little in way of actions to back up their words. We must caution those who have confused waiting for Christ’s return with inactivity. There is a stern warning for those who sit on pews each week yet never engage in the work of God or who have many Bibles on their shelves yet never engage in the Word of God. The believer's purpose here is the ministry of reconciliation in which all we are called to be ambassadors of Christ, not idle bystanders.  

Secondly, we must encourage the fainthearted. It is quite common for a new believer to enter into their Christian life with a high level of zeal and enthusiasm, and it is equally commonplace for that fervor to fade with time. When a brother or sister in Christ suffers from a heart becoming faint, or has their confidence shaken by circumstance, it falls upon us to gently remind them of the never-changing nature of God: His immovable presence and His unfailing promises. So that we can encourage each other to have a faith like that of Job, who vowed to trust God, even in the face of his own death.

Thirdly, we are to help the weak. The simple truth is that none of us are as strong as we often think we are, and when we see a fellow Christian lacking courage or strength, we are to come alongside them and help carry the load, reminding them of God's all-sufficient grace and help in times of need. Helping others is mandatory for the Christian, and it is with good reason that the writer of Ecclesiastes reminds us that "a threefold cord is not quickly broken." [4:12]

Finally, we are urged to be patient with everyone who is idle, fainthearted, or weak. After all, is not God patient with us? Has He not postponed the judgment on our sins that we might seek Christ, taking His offer of bearing God’s wrath in our place and offering forgiveness? Does He not allow our prodigal hearts to return home after we have strayed away? Just as God is patient, we too must be patient with others.

Each follower of Christ will mature in an individual way, unique to them. This may not always line up with our desire or expectation for their growth. In such cases, we must be mindful that it is not our duty to cause growth, but to admonish, encourage, help, and remain patient always.