Nahum 3:12–13 Faith the size of a mustard seed is power

Have we become weak in our faith, not expecting God to answer our prayers, instead relying on our own strength?

In the Old Testament God dealt with Israel, and it is now profitable  for teaching the Body of Christ. Our enemies are now spiritual, and not with man, prayer and supplications are our weapons for warfare with the enemy. He comes only to kill, steal and destroy our faith. 

Ephesians 6:12 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.

God thwarts the plans of our enemy when we place all of our trust in Him.

Isaiah 19:16 In that day Egypt will be like women, and will be afraid and fear because of the waving of the hand of the LORD of hosts, which He waves over it.

Jeremiah 51:30 

The mighty men of Babylon have ceased fighting,

They have remained in their strongholds;

Their might has failed,

They became like women;

They have burned her dwelling places,

The bars of her gate are broken.

God’s faithfulness to His Covenant people  shows us His faithfulness extends to all who believe. He is unchanging and promises He will never leave you. 

Christ within us is the hope of glory.

Romans 15:4

4 For whatever things were written before were written for our learning, that we through the patience and comfort of the Scriptures might have hope.

Through patience (endurance) and the comfort (or encouragement) of Scripture, believers learn that they have hope. In this case, if strong believers are patient with the scruples of the weak, they have hope of being rewarded. The NKJV Study Bible

Here Paul reminds the Roman believers that old testament is a source of encouragement and instruction for Christians. Faithlife Study Bible

Nahum 3:12–13

12 All your strongholds are fig trees with ripened figs: If they are shaken, They fall into the mouth of the eater. 13 Surely, your people in your midst are women! The gates of your land are wide open for your enemies; Fire shall devour the bars of your gates. The New King James Version

The Hebrew term used here plays on gender stereotypes to convey the idea of weakness or fright. 

The gates of a city were heavily fortified entryways granting access inside the city. Ancients prepared for siege by ensuring that they had an adequate supply of water. Heavily fortified areas of the city typically built with clay bricks. Assyria’s proximity to the Tigris River and its channels meant that the region had an abundance of clay. Faithlife Study Bible

Nahum satirically describes the strongholds of Nineveh as being so easily defeated that they would be like fruit trees that drop their figs into waiting mouths. The NKJV Study Bible

2 Timothy 3:16 All Scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness,

Isaiah 45:2 

‘I will go before you

And make the crooked places straight;

I will break in pieces the gates of bronze

And cut the bars of iron.