You know there are just some passages in the Bible that are bound to be abused by folks along the way. I don't believe it is their intention to abuse the text. I believe they are well meaning Jesus followers who have not been taught better by their pastors (supposed teachers of the text). If they have a pastor who teaches well and they just don't engage in the life of the church and they make such errors, perhaps they need to check the reality of their salvation (2 Cor 13:5). Jeremiah 29:11 is one of those, and Isaiah seems to be one that I keep hearing that is radically abused.
Just for reference, here it is:
"...but they who wait for the LORD shall renew their strength; they shall mount up with wings like eagles; they shall run and not be weary; they shall walk and not faint."
I love it. But, the problem is that we westerners have a tendency to not read it in its proper context. We tend to superimpose our context on this text.
For example: As I go about my day doing my thing (continuing to be a workaholic, pursuing more material stuff at the stuff mart, bigger and nicer houses and cars, bigger and costlier toys, neglecting wife, husband and kids, not properly engaging the world through the vehicle of the church, etc.) God will cause me to have strength to do all that I need to.
In other words, because I say I am a Jesus follower, God will strengthen me to do my thing each day as it needs to be done.
It's subtle, but wrong.
From what I can tell, God's people are in exile in Babylon and languishing away in a land that is not home while enslaved by people who do not know the Lord and they are forced to comply with their captors while longing to return home and trying to remain faithful to the Lord.
In other words they are carrying a load that is humanly impossible to carry while in captivity resulting from not loving the Lord with all their heart, mind and strength.
The promise is this: when you are burdened so far beyond your ability to bear it with what God the Father in grace and love and placed upon you to train you to be his child because you bear his name and are forever adopted as his kid, when you are doing his thing, his way in his time, even if it means you are a freak to the world around you because of what you value and sacrifice for the sake of something better, their strength will be renewed, they will mount up on wings like eagles, they will run and not be weary, they will walk and not faint.
It what scenario are you? In which scenario am I?
Promises are not all that valuable when posh and luxury are present and pursued. Promises take on value when in deep and discomfort is the "soup de jour". This is such a promise that only makes sense when we are loaded with God's stuff and can't bear it unless he causes us to.
See 2 Corinthians 1:1-11 for how Paul experience a crushing from the Lord so that he could taste what it was like for the Lord to cause him to be sustained in the middle of the crushing.
That is where Isaiah 40:31 take flight.