Why can't we fix our own weaknesses, and what should we do instead?
We cannot fix our own weaknesses because they involve the invisible realm of the Spirit, beyond human ability. Instead, the Holy Spirit, who indwells believers according to Paul's teaching, helps our infirmities. We should let God do it, trusting Him with patience and hope while waiting for His promised fruition.
Les teaches that verse 26 moves into a deeper area: the Holy Spirit, now indwelling believers according to Paul, also helps our infirmities, our weaknesses. Since the problem is invisible and in the realm of the Spirit, there is not much we can do about it ourselves; instead, we let God do it. This fits the surrounding discussion of faith and hope: we hope for what we do not see and wait patiently, not trying to push God faster, never losing sight that it will happen, including Christ's return.
Likewise the Spirit also helpeth our infirmities: for we know not what we should pray for as we ought: but the Spirit itself maketh intercession for us with groanings which cannot be uttered.
More Questions
Why can't we fix our weaknesses by our own effort?
Because our weaknesses are in the invisible spiritual realm, there is not much we can do about them ourselves; we must let God do the work.
Does the Holy Spirit help us with our weaknesses?
The Holy Spirit, who now indwells believers, also helps them in their weaknesses.