Albert Barnes Commentary Psalms 84:11

"For Jehovah God is a sun and a shield: Jehovah will give grace and glory; No good thing will he withhold from them that walk uprightly." — Psalms 84:11 (ASV)

For the Lord God is a sun — The Septuagint and the Latin Vulgate render this, “For the Lord loves mercy and truth.” Our translation, however, is the correct one. The sun gives light, warmth, and beauty to the creation; so God is the source of light, joy, and happiness to the soul. Compare Isaiah 60:19; Revelation 21:23; Revelation 22:5.

And shield — See Psalm 84:9.

The Lord will give grace and glory — Grace, or favor, here; glory, or honor, in the world to come. He will bestow all needful favor on his people in this life; he will admit them to glory in the world to come. Grace and glory are connected. The bestowal of the one will be followed by the other (Romans 8:29–30). The one who partakes of the grace of God on earth will partake of glory in heaven. Grace comes before glory; glory always follows where grace is given.

No good thing will he withhold ... — Nothing really good; nothing that anyone really needs; nothing pertaining to this life, nothing necessary to prepare for the life to come. Compare 1 Timothy 4:8; Philippians 4:19.