'Weakness' in the Bible

While we were still helpless [powerless to provide for our salvation], at the right time Christ died [as a substitute] for the ungodly.

I am using a human analogy because of the weakness of your flesh. For just as you offered the parts of yourselves as slaves to moral impurity, and to greater and greater lawlessness, so now offer them as slaves to righteousness, which results in sanctification.

In the same way the Spirit also joins to help in our weakness, because we do not know what to pray for as we should, but the Spirit Himself intercedes for us with unspoken groanings.