Hold Fast

Strengthen ye the weak hands, and confirm the feeble knees. Say to them that are of a fearful heart, Be strong, fear not: behold, your God will come with vengeance, even God with a recompence; he will come and save you. Isa 35:3-4 

God's prophets and ministers are in a special manner charged, by virtue of their office, to strengthen the weak hands, to comfort those who could not yet recover the fright they had been put into by the Assyrian army with an assurance that God would now return in mercy to them. This is the design of the gospel, 1. To strengthen those that are weak and to confirm them - the weak hands, which are unable either to work or fight, and can hardly be lifted up in prayer, and the feeble knees, which are unable either to stand or walk and unfit for the race set before us. The gospel furnishes us with strengthening considerations, and shows us where strength is laid up for us. Among true Christians there are many that have weak hands and feeble knees, that are yet but babes in Christ; but it is our duty to strengthen our brethren (Luk 22:32), not only to bear with the weak, but to do what we can to confirm them, Rom 15:1; 1Th 5:14. It is our duty also to strengthen ourselves, to lift up the hands which hang down (Heb 12:12), improving the strength God has given us, and exerting it. 2. To animate those that are timorous and discouraged: Say to those that are of a fearful heart, because of their own weakness and the strength of their enemies, that are hasty (so the word is), that are for betaking themselves to flight upon the first alarm, and giving up the cause, that say, in their haste, "We are cut off and undone" (Psa 31:22), there is enough in the gospel to silence these fears; it says to them, and let them say it to themselves and one to another, Be strong, fear not. Fear is weakening; the more we strive against it the stronger we are both for doing and suffering; and, for our encouragement to strive, he that says to us, Be strong has laid help for us upon one that is mighty.  (Matthew Henry)

Strengthen ye the weak hands, and confirm the feeble knees. Is 35:3

Strengthen ... hands ... confirm ... knees — The Hebrew for "strengthen" refers to the strength residing in the hand for grasping and holding a thing manfully; "confirm," to the firmness with which one keeps his ground, so as not to be dislodged by any other [Maurer]. Encourage the Jews, now desponding, by the assurance of the blessings promised. (JFB)

Note:  Strengthen then means, "hold fast."  To what?  To the promises of God.  (AAB)

My righteousness I hold fast, and will not let it go: my heart shall not reproach me so long as I live. Job 27:6 

Prove all things; hold fast that which is good. 1Th 5:21 

Hold fast the form of sound words, which thou hast heard of me, in faith and love which is in Christ Jesus. 2Ti 1:13 

But Christ as a son over his own house; whose house are we, if we hold fast the confidence and the rejoicing of the hope firm unto the end. Heb 3:6 

Seeing then that we have a great high priest, that is passed into the heavens, Jesus the Son of God, let us hold fast our profession. Heb 4:14 

Let us hold fast the profession of our faith without wavering; (for he is faithful that promised;) Heb 10:23