Summary: In a hymn of praise to God’s goodness in Psalm 36, three basic characteristics are presented of the Father as the God of "the Gospel of Light". In this we see 1) Light from His Person (Ps. 36:5-6), 2) Light for His People (Ps. 36:7-9) and 3) Light from His Protection (Ps. 36:10-11).
Psalm 36:5-11  Your steadfast love, O LORD, extends to the heavens, your faithfulness to the clouds.  Your righteousness is like the mountains of God; your judgments are like the great deep; man and beast you save, O LORD.  How precious is your steadfast love, O God! The children of mankind take refuge in the shadow of your wings.  They feast on the abundance of your house, and you give them drink from the river of your delights.  For with you is the fountain of life; in your light do we see light.  Oh, continue your steadfast love to those who know you, and your righteousness to the upright of heart!  Let not the foot of arrogance come upon me, nor the hand of the wicked drive me away. (ESV)
God’s “steadfast love” seems to be the most important attribute of God in Psalm 36. It is the first attribute David mentions, and he refers to God’s “steadfast love” three times in these verses (vv. 5, 7, 10). “Steadfast love” (“lovingkindness” or “unfailing love” in some translations) is God’s covenant love. He is faithful and loyal to his people just as a good man loves his wife and is faithful to her. When David says that God’s “steadfast love … extends to the heavens” (v. 5), he means there are no limits to his love. When our children were young, one of their their favorite books was Guess How Much I Love You? In the book, Little Nutbrown Hare tries to show his daddy how much he loves him—as high as he can reach and as far as he can hop. But Big Nutbrown Hare can reach higher and hop farther, and he loves him back even more. “I love you all the way down the lane as far as the river,” cried Little Nutbrown Hare. “I love you across the river and over the hills,” said Big Nutbrown Hare. Finally, Little Nutbrown Hare looked up at the sky and said, “I love you all the way to the moon,” and he fell asleep. Big Nutbrown Hare lay down next to him and whispered, “I love you right up to the moon—and back.” God’s “steadfast love” (v. 5) is even better. He loves (His children) to the moon and beyond! His unfailing love is as vast as the immeasurable vastness of space. There are no limits to his loving commitment to his people. ( Johnston, J. A. (2015). Preaching the Word: The Psalms: Rejoice, the Lord Is King—Psalms 1 to 41. (R. K. Hughes, Ed.) (Vol. 1, pp. 372–373). Wheaton, IL: Crossway.)
For the redeemed, God calls us His children. Scripture is a record of how much he loves us as His children. His present care and control in His providence show us His love for us. The assurances in His word and by His Spirit of eternal life, as well as the evidence of Christ's resurrection continue to show His great love. The Gospel itself is a picture of God's love for us. The Gospel stems from the goodness of God. In a hymn of praise to God’s goodness in Psalm 36, three basic characteristics are presented of the Father as the God of "the Gospel of Light". In this we see 1) Light from His Person (Ps. 36:5-6), 2) Light for His People (Ps. 36:7-9) and 3) Light from His Protection (Ps. 36:10-11)
The Father is seen as the God of "the Gospel of Light" as seen in:
1) Light from His Person (Ps. 36:5-6)
Psalm 36:5-6  Your steadfast love, O LORD, extends to the heavens, your faithfulness to the clouds.  Your righteousness is like the mountains of God; your judgments are like the great deep; man and beast you save, O LORD. (ESV)
The most important of God’s attributes from the perspective of this psalm is hesed, (which is translated here as steadfast love) in other translations it is rendered as:) “unfailing love” or “lovingkindness.” It is important because it begins the list of attributes (in v. 5) and closes it (in v. 7). It also reappears in the closing prayer (in v. 10) (Boice, J. M. (2005). Psalms (Pbk. ed.) (311). Grand Rapids, Mich.: Baker Books). Alexander Maclaren has a sermon on this psalm in which he unfolds the meaning of the term, calling it goodness, mercy, and grace. Describing this steadfast love he says: “All his goodness is forbearance, and his love is mercy, because of the weakness, the lowliness, and the ill desert of us on whom the love falls. … The first and last, the Alpha and Omega of God, beginning and crowning and summing up all his being and his work, is his mercy, his lovingkindness.”(Alexander Maclaren, Expositions of Holy Scripture, vol. 3, The Psalms, Isaiah 1–48 (Grand Rapids: Eerdmans, 1959), 229–30.)