Why are you God strong ?  Because  :

“You are of God, little children, and have overcome them, because He who is in you is greater than he who is in the world”. (1 John 4:4 NKJV).

“The Lord  is my light and my salvation; Whom shall I fear? The Lord  is the strength of my life; Of whom shall I be afraid?”(Psalms 27:1 NKJV).

“The Lord  is  my strength and my shield; My heart trusted in Him, and I am helped; Therefore my heart greatly rejoices, And with my song I will praise Him”.(Psalms 28:7 NKJV).

“And lest I should be exalted above measure by the abundance of the revelations, a thorn in the flesh was given to me, a messenger of Satan to buffet me, lest I be exalted above measure. Concerning this thing I pleaded with the Lord three times that it might depart from me. And He said to me, “My grace is sufficient for you, for My strength is made perfect in weakness.” Therefore most gladly I will rather boast in my infirmities, that the power of Christ may rest upon me. Therefore I take pleasure in infirmities, in reproaches, in needs, in persecutions, in distresses, for Christ’s sake. For when I am weak, then I am strong”. ( 2 Corinthians 12:7‭-‬10 NKJV).

THEREFORE   :

“I can do all things through Christ who strengthens me”. (Philippians 4:13 NKJV).
SO:

“Finally, my brethren, be strong in the Lord and in the power of His might. Put on the whole armor of God, that you may be able to stand against the wiles of the devil. For we do not wrestle against flesh and blood, but against principalities, against powers, against the rulers of the darkness of this age, against spiritual hosts of wickedness in the heavenly places.  Therefore take up the whole armor of God, that you may be able to withstand in the evil day, and having done all, to stand. Stand therefore, having girded your waist with truth, having put on the breastplate of righteousness, and having shod your feet with the preparation of the gospel of peace; above all, taking the shield of faith with which you will be able to quench all the fiery darts of the wicked one. And take the helmet of salvation, and the sword of the Spirit, which is the word of God; praying always with all prayer and supplication in the Spirit, being watchful to this end with all perseverance and supplication for all the saints—”(Ephesians 6:10‭-‬18 NKJV).