Is anyone among you in trouble? Let them pray. Is anyone happy? Let them sing songs of praise. 14 Is anyone among you sick? Let them call the elders of the church to pray over them and anoint them with oil in the name of the Lord. 15 And the prayer offered in faith will make the sick person well; the Lord will raise them up
In James 5 we are reminded that this life here on earth will have trouple. Workers are deprived of their wages, people are sick. etc. The chapter also speaks about prayer as well. The laborer cries out to God, the sick pray for healing. Put the two thoughts together and we get another mark of a mature Christian: one who is prayerful in spite of trouble. Instead of giving up when troubles come the mature believer continues to pray and seek God.
The thing with prayer is that it is an issue of faith - we do not pray if we do not believe. When we pray we are submitting to God and admitting that we need help. When we pray we are confessing that God is powerful and mighty and able to save us.
The mature believer prays, believing that God is able to work mightily on our behalf. The mature Christian believes that God can, God will and even if He doesn't we will still trust Him.