103:1 Bless the LORD. The exhortation to “bless the LORD” occurs six times in this psalm (verses l,2,20, 21,22). Men or angels can bless the Lord when they praise or thank Him, or—especially—when they worship Him (that is, obey His will). He blesses us with “life, and breath, and all things” (Acts 17:25), and it blesses Him when we “forget not all His benefits” (Psalm 102:2).
103:3 healeth. This promise has its primary fulfillment in our resurrection bodies, when all diseases will be cured forever, even the greatest disease, that of aging and dying itself.
103:5 like the eagle’s. Instead of being forlorn like “an owl of the desert” or helpless like “a sparrow alone upon the housetop,” as in the previous psalm (Psalm 102:6-7), the trusting believer may “mount up with wings as eagles” (Isaiah 40:31).
103:11 heaven is high. The Lord, in picturing His infinite mercy, uses the infinite height of the heavens as the appropriate simile, thus predating the most modern concepts of observational astronomy.
103:12 east is from the west. Here is a second figure applied to the limitless scope of God’s forgiving grace. One can travel east (or west) forever without coming to its end. This perfectly fits the idea of a global earth.