Walking with Jesus

In 1781, George Heath (no relation) penned the lyrics to the hymn ,
"My Soul, Be on Thy Guard":

My soul, be on thy guard;
ten thousand foes arise;
the hosts of sin are pressing hard
to draw thee from the skies.

O watch, and fight, and pray;
the battle ne'er give o'er;
renew it boldly every day,
and help divine implore.

Ne'er think the vict'ry won,
nor once at ease sit down;
the arduous work will not be done
till thou hast got the crown.

Fight on, my soul, till death
shall bring thee to my God;
He'll take thee, at thy parting breath,
up to His rest above.

How does this hymn compare with the words of the 23rd Psalm?

The Lord is my shepherd; I shall not want.
    He makes me lie down in green pastures.
He leads me beside still waters.
    He restores my soul.
He leads me in paths of righteousness
    for his name's sake.
Even though I walk through the valley of the shadow of death,
    I will fear no evil,
for you are with me;
    your rod and your staff,
    they comfort me.
You prepare a table before me
    in the presence of my enemies;
you anoint my head with oil;
    my cup overflows.
Surely goodness and mercy shall follow me
    all the days of my life,
and I shall dwell in the house of the Lord
    forever.

How can the words of the 23 Psalm guide us in staying on guard, walking with Jesus?