2 Timothy 2:1 - Power in Jesus!

2 Tim 2:1 (KJV) Be strong in the grace that is in Christ Jesus.

2 Tim 2:1 (TLB)  Be strong with the strength Christ Jesus gives
you.

2 Tim 2:1 (TEV)  Be strong through the grace that is ours in
union with Christ Jesus.

How can someone be strong in grace? Grace means undeserved
favor. Just as we are saved by grace (Ephes. 2:8, 9), we should live by
grace (Colossians 2:6). This means trusting completely in Christ and
'his' power, and not trying to live for Christ in our strength alone.
Receive and utilize Christ's power. He will give you the strength to do
his work. [Life Application SB]

As our trials increase, we need to grow stronger in that which
is good; our faith stronger, our resolution stronger, our love to
God and Christ stronger. This is opposed to our being strong in our
own strength. All Christians, but especially ministers, must be
faithful to their Captain, and resolute in his cause. The great care of a
Christian must be to please Christ. [Matthew Henry]

Be strong in the Lord, and in the power of his might. Put on the
whole armour of God, that ye may be able to stand against the wiles of
the devil. (Eph 6:10,11 KJV)

Spiritual strength and courage are needed for our spiritual
warfare and suffering. Those who would prove themselves to have true
grace, must aim at all grace; and put on the whole armour of God, which
he prepares and bestows. The Christian armour is made to be worn;
and there is no putting off our armour till we have done our
warfare, and finished our course.  [Matthew Henry]

We have no enemies but the enemies of God.  Our fights are not
against men but against spiritual wickednesses.  We war with the devil
and the blasphemy and error and despair which he brings into the
field of battle.  We fight with all the armies of sin - impurity,
drunkenness, oppression, infidelity, and ungodliness.  With these we contend
earnestly, but not with sword or spear; the weapons of our warfare are not
carnal.
Jehovah, our God, abhors everything which is evil, and,
therefore, He goeth with us to fight for us in this crusade.  He will save
us, and He will give us grace to war a good warfare and win the
victory.  We may depend upon it that if we are on God's side God is on
our side.  With such an august ally the conflict is never in the
least degree doubtful.  It is not that truth is mighty and must
prevail but that might lies with the Father who is almighty, with Jesus
who has all power in heaven and in earth, and with the Holy Spirit
who worketh His will among men.
Soldiers of Christ, gird on your armor.  Strike home in the name
of the God of holiness, and by faith grasp His salvation.  Let not
this day pass without striking a blow for Jesus and holiness.
[Charles Spurgeon; Time with God devotional SB]