We hear your heart in this season of feeling unmotivated and tired, even in spiritual things, and we join with you in bringing this before the Lord together in Jesus' name.
You are right that feeling tired or worn out while reading the Bible or praying is not in itself sin. Our bodies and minds have limits, and God as our Creator knows our frame. He makes us to lie down in green pastures and leads us beside still waters, he restores our soul, Psalm 23:2-3. Jesus himself said to his disciples, Come away into a deserted place, and rest awhile, Mark 6:31, for even they had no leisure so much as to eat. And our Lord invites us, Come to me, all you who labor and are heavily burdened, and I will give you rest. Take my yoke upon you, and learn from me, for I am gentle and humble in heart and you will find rest for your souls, Matthew 11:28-29. Fatigue does not mean you have failed or that your faith is false, God understands our weakness.
At the same time we want to gently encourage you not to remain in a place of low motivation without seeking the deeper renewal God wants to give. While tiredness is not sin, we are also called to press on and not grow weary in well doing. Scripture says, Let us not be weary in doing good, for we will reap in due season, if we do not give up, Galatians 6:9. And, He gives power to the weak. He increases the strength of him who has no might, Isaiah 40:29. And those who wait for Yahweh will renew their strength. They will mount up with wings like eagles. They will run, and not be weary. They will walk, and not faint, Isaiah 40:31. Sometimes lack of motivation can be simple physical need for sleep, rest, nourishment and pacing, and sometimes it can be a sign that we need to confess spiritual dryness, distraction, or discouragement and ask God to stir our affections again. We encourage you to consider practical steps as you mentioned, resting well, keeping a consistent but grace filled rhythm in the Word, praying even short honest prayers for strength, varying your study, and walking with other believers who can encourage you.
We also noticed your request did not mention the name of Jesus Christ, and we want to lovingly remind you that it is only through Jesus that we have access to the Father and find true rest. Jesus said, I am the way, the truth, and the life. No one comes to the Father, except through me, John 14:6. And, There is salvation in none other, for neither is there any other name under heaven, that is given among men, by which we must be saved, Acts 4:12. If you have not already, we encourage you to place your trust in Jesus Christ, believing that He died for your sins and rose again, and to call upon His name, for whoever will call on the name of the Lord will be saved, Romans 10:13. It is in His name we pray and find strength for each day.
We pray together for you now.
Father, we lift up this dear one to you in the name of Jesus Christ. You see the weariness and the lack of motivation, and you know every burden. We ask that you grant restorative rest and renew a hunger for your Word and your presence. Forgive us where we have leaned on our own strength or allowed discouragement to linger, and fill us with your Spirit. Teach us to wait upon you that our strength may be renewed, and help us to be diligent to seek you while also receiving the rest you provide. Draw this heart closer to Jesus, that in Him there would be joy, peace, and a steady desire to know you more. Give wisdom for daily rhythms of work, rest, and devotion, and let your Word be fresh and life giving again. We ask this in the precious name of Jesus, our rest and our strength, Amen.