As I go through my twilight years there is a noticeable difference in my energy level. What I used to accomplish in a half day now takes two days. If I ever develop the horrible Alzheimer’s disease, perhaps the only blessing will be to no longer remember the strength and stamina of my younger years and, therefore, a much lower expectation of what I am able to do. 
In times when we contemplate our weakness and God’s strength, we are often drawn to one of the more familiar revelations of the apostle Paul’s life from which we can receive blessing and encouragement. As he preached to the church at Corinth in II Corinthians 12, Paul wanted them to understand that, although he had received special visions and revelations of the Lord, he had been given a thorn in the flesh and ‘should not be exalted above measure’ (v.7). Even though he had asked the Lord three times to remove the thorn, Jesus responded, “My grace is sufficient for thee: for my strength is made perfect in weakness” (v.9.). Paul’s response was not one of mere acceptance but rather one of complete trust in the Lord’s strength: “Therefore, I take pleasure in infirmities, in reproaches, in necessities, in persecutions, in distresses for Christ’s sake: for when I am weak, then I am strong” (v.10).
We often equate weakness with the lack of physical strength. As we age our physical strength will inevitably wear down. Our spiritual strength, however, can be sustained and even grow regardless of our age. The same Holy Spirit who raised Jesus from the dead lives in us and gives us endless energy and boundless strength.
In John 6 we read an account of Jesus speaking to the Jews at Capernaum during which Jesus ‘laid it all out’…...who He was, why He came, and what it would take to follow Him and receive everlasting life. After hearing Jesus’ teaching, the response of many of His disciples was quick and spontaneous, “This is an hard saying; who can hear it?” (v.60). The 6th chapter of John begins with many people following Jesus. It ends with many people turning away from Him. It is not so much that the hearers found Jesus’ teaching difficult to understand, but they did not like its content. It seems that they were particularly offended by His claim to be ‘the bread of life’ and the only way to the Father. When many turned away, Jesus asked the Twelve, “Will you also go away?”, to which Peter answered, “Lord, to whom shall we go? Thou hast the words of eternal life. And we believe and are sure that thou are that Christ, the Son of the living God.” (v.v.68-69). 
As Christians we sometimes find the teachings of Jesus very hard to live out. It may even seem like people dislike us because of our faith. Following Jesus is a tough call, but it is the only way to life in all its fullness. This fullness of life comes, as Jesus explains, from the Holy Spirit. Although there is a cost in following Jesus, the benefits far outweigh the cost. We simply need to trust Him and draw on the power of the Holy Spirit to provide endless energy and boundless strength.