Because the New Testament was written over such a short period of time there are a lot of things that are missing from the NT cannon. We have the letters of Paul and a few of the first apostles; James, John, Peter, Jude. I wonder if their expectation of the return of Christ made them not care to write about everything that they dealt with in day to day living. History in the New Testament is almost by accident.
One thing that is missing is how to grow old in Christ. It seems that the early apostles had no sense of growing older even though they are all dead and gone today. To find anything on growing older we have to search the Old Testament where there is more information available.
"Even to your old age, I am He, and even to gray hairs I will carry you! I have made, and I will bear; Even I will carry, and will deliver you" Isa.46:4
"Do not cast me off in the time of old age; do not forsake me when my strength fails." Psalm 71:9
In the first century AD no one lived as long as we do. It would be hard for those who lived short lives to give us who live longer useful advice.
"And lo, I am with you always, even to the end of the age." Mat. 28:20
"Remember now your Creator in the days of your youth, before the difficult days come, and the years draw near when you say, I have no pleasure in them." Eccl. 12:1
God bless us, everyone!