The Bible's book of Isaiah speaks of God's love for us and of His ability and willingness to help us. Isaiah was a prophet, a spiritual seer-one who knew not only the future but also what God, our heavenly Father, does for us. He prophesied the coming of the Messiah, or Christ, which Christ Jesus fully expressed. You'll find in Peloubet's Bible Dictionary this comment by Professor Moulton: "It may be safely asserted that nowhere else in the literature of the world have so many colossally great ideas been brought together within the limits of a single work. . . . Even in literary form the world has produced nothing greater than Isaiah."
Perhaps one of the most beloved things the book of Isaiah has to say to all of us is this: "Fear thou not; for I am with thee: be not dismayed; for I am thy God: I will strengthen thee; yea, I will help thee; yea, I will uphold thee with the right hand of my righteousness" (41:10). I like to remind myself of these promises often, for God will surely quiet fear. He will keep us from being dismayed. He will strengthen and uphold us. Through God's power we have energy to carry on with whatever work we have to do.
There is more about the strength God gives man in the book of Psalms. Many of the psalms are attributed to the great king of Israel, David. As a youth, tending his father's sheep, David had learned how to depend on God while he was out caring for the flocks. When a lion and a bear carried off lambs at different times, David saved the lambs and alone killed both the lion and the bear, recognizing that he had power from God (see I Samuel 17:34-37). Early in life he learned to depend on God for strength and courage. Here is one psalm the Bible says is David's, which I think you will like and find helpful: "What is man, that thou art mindful of him? and the son of man, that thou visitest him? For thou hast made him a little lower than the angels, and hast crowned him with glory and honour. Thou madest him to have dominion over the works of thy hands; thou hast put all things under his feet" (Psalms 8:4-6). How wonderful to know these truths and feel the assurance they give. God has given each of us dominion equal to the task at hand.
Christian Science is an explanation of the laws of God found in the Bible. Isaiah, David, Jesus, and many others felt the strength behind God's laws. In the Bible's teachings is found this Science, the Science of Christ, which can be studied and practiced. This brings an understanding of God as Spirit and of us as spiritual, not material. We are the likeness of God, according to the Bible. Understanding this heals us and solves problems in daily life. One of the areas where Christian Science can help is in healing feelings of weakness and fatigue.
Being a wife and mother, as well as a homemaker, I often needed to deal with weariness. On this subject, the woman who discovered Christian Science, Mary Baker Eddy, wrote something helpful: "The supposed laws which result in weariness and disease are not His [God's] laws, for the legitimate and only possible action of Truth is the production of harmony" (Science and Health with Key to the Scriptures, p. 183). Christian Science explains that Truth is synonymous with God. Only the laws of God are true; not "the supposed laws which result in weariness and disease." Later the book describes the remedy for fatigue in these words: "The scientific and permanent remedy for fatigue is to learn the power of Mind over the body or any illusion of physical weariness, and so destroy this illusion, for matter cannot be weary and heavy-laden" (p. 217). Because we are spiritual, our strength and ability are from God, the divine Mind. They are infinite and inexhaustible.
After learning of the power of God, I found quick healing of physical weariness. Through the years I did this by praying, reminding myself of my spiritual identity. Now I can rejoice that I seldom feel weary. I've taken daylong car rides without feeling tired. Now spring and fall housecleaning are a joy for me. When I have felt weary from work or recreation, I have considered the truth of God and felt rested as a result.
It is a glorious feeling never to feel tired, and it is possible to seek and find the spiritual energy Isaiah and the Psalmist spoke of.