Romans 8: 26 Likewise, the Spirit also helps our infirmities: for we know not what we should pray for as we ought: but the Spirit itself makes intercession for us with groanings which cannot be uttered.
Every one of the disciples, who stayed the course with Christ, were brought to maturity, for even the doubting Thomas, and the impulsive Peter, and the sons of Zebedee who were prone to violence anger and revenge, were all thoroughly converted by The Spirit of God working in their hearts, and thus were brought to maturity. This is the reason why we have encouraged you to stay the course with Christ, no matter what might come your way.
All those who stay will be made partakers of the mature Christlike character, in the fulness of time. Some will be severely tempted to let go their hold on Jesus because of deep seated flaws in their lives but, if we hang in there, God who has promised us to finish the work He has started in our hearts, will bring it to completion if we were to stay the course with Him. The Christian race is never about speed, it is about endurance, and thus, all who “Endure” to the end will be saved.
[The Desire of Ages pp 295] All of the disciples had serious faults when Jesus called them to His service. Even John, who came into closest association with the meek and lowly One, was not himself naturally meek and yielding. He and his brother were called the sons of thunder. While they were with Jesus, any slight shown to Him aroused their indignation and combativeness. Evil temper, revenge, the spirit of criticism, were all in the beloved disciple. He was proud, and ambitious to be first in the kingdom of God.
Romans 8:27 And He that searches the hearts, knows what is the mind of the Spirit because he makes intercession for the saints according to the will of God.
May The Lord add His blessing to the study of His word. God bless!