Psalm 21:1
21:1 To the chief Musician, A Psalm of David. The king shall
     {a} joy in thy strength, O LORD; and in thy salvation how
     greatly shall he rejoice!

     (a) When he will overcome his enemies, and so be assured of
         his calling.

Psalm 21:3
21:3 For thou {b} preventest him with the blessings of goodness:
     thou settest a crown of pure gold on his head.

     (b) You declared your liberal favour toward him before he
         prayed.

Psalm 21:4
21:4 {c} He asked life of thee, [and] thou gavest [it] him,
     [even] length of days for ever and ever.

     (c) David not only obtained life, but also assurance that
         his posterity would reign forever.

Psalm 21:6
21:6 For thou hast made him most {d} blessed for ever: thou hast
     made him exceeding glad with thy countenance.

     (d) You have made him your blessings to others, and a
         perpetual example of your favour forever.

Psalm 21:8
21:8 {e} Thine hand shall find out all thine enemies: thy right
     hand shall find out those that hate thee.

     (e) Here he describes the power of Christ's kingdom against
         the enemies of it.

Psalm 21:9
21:9 Thou shalt make them as a fiery oven in the time of thine
     anger: the LORD shall swallow them up in his {f} wrath, and
     the fire shall devour them.

     (f) This teaches us patiently to endure the cross till God
         destroys the adversary.

Psalm 21:11
21:11 For they {g} intended evil against thee: they imagined a
      mischievous device, [which] they are not able [to
      perform].

      (g) They laid as it were their nets to make God's power
          bend to their wicked enterprises.

Psalm 21:12
21:12 Therefore shalt thou make them {h} turn their back, [when]
      thou shalt make ready [thine arrows] upon thy strings
      against the face of them.

      (h) As a mark to shoot at.

Psalm 21:13
21:13 {i} Be thou exalted, LORD, in thine own strength: [so]
      will we sing and praise thy power.

      (i) Maintain your Church against your adversaries that we
          may have ample opportunity to praise your Name.