2 Corinthians 12:9 - Strength in Christ not Self.

My grace is sufficient for you, for my power is made perfect in
weakness. 2 Cor 12:9 (NIV)

Here is recorded one of the greatest spiritual truths in all of
Scripture: God's strength is made perfect (complete, mature) in our
weakness. Verse 10 expresses it again in summary fashion: "For when I am
weak, then I [through Christ's power] am strong." [Believer's SB]

When we are strong in abilities or resources, we are tempted to
do God's work on our own, and that can lead to pride. When we are
weak, allowing God to fill us with 'his' power, then we are stronger
than we could ever be on our own. God does not intend for us to seek
to be weak, passive, or ineffective--life provides enough
hindrances and setbacks without us creating them. When those obstacles
come, we must depend on God. Only his power will make us effective for
him and will help us do work that has lasting value. [Life
Application SB]

Prayer is a salve for every sore, a remedy for every malady; and
when we are afflicted with thorns in the flesh, we should give
ourselves to prayer. If an answer be not given to the first prayer, nor to
the second, we are to continue praying. Troubles are sent to teach
us to pray; and are continued, to teach us to continue instant in
prayer....When God does not take away our troubles and temptations, yet, if he
gives grace enough for us, we have no reason to complain. Grace
signifies the good-will of God towards us, and that is enough to enlighten
and enliven us, sufficient to strengthen and comfort in all
afflictions and distresses. His strength is made perfect in our weakness.
[Matthew Henry Commentary]

If you will seek the Lord and be converted every day; if you
will of your own spiritual choice be free and joyous in God; if with
gladsome consent of heart to His gracious call you come wearing the yoke
of Christ,--the yoke of obedience and service,--all your murmurings
will be stilled, all your difficulties will be removed, all the
perplexing problems that now confront you will be solved.  MB100,1