“Let justice roll down like waters and righteousness like an ever-flowing stream” (Amos5:24NASB)
There is not a great deal of joy to be gleaned from the writings of this prophet, who was reluctant to describe himself as such having been a shepherd and fig grower to whom God had revealed a message for His people (7:14).  God is frequently depicted by Amos as a roaring lion; not of the relatively cuddly ‘Aslan’ variety but a beast who was decidedly angry and much to be feared, even by His own people:
“Alas, you who are longing for the day of the lord, for what purpose will the day of the lord be to you? It will be darkness and not light; as when a man flees from a lion and a bear meets him, or goes home, leans his hand against the wall and a snake bites him. Will not the day of the lord be darkness instead of light, even gloom with no brightness in it?”
The “Day of the Lord” is a recurring theme in the Prophets as it is in the New Testament; these Israelites were anticipating it being a day of retribution – punishment for the wicked and vindication for God’s faithful people. By the wicked they will no doubt have had “ignorant Gentiles” in mind whilst their ill-founded confidence rested in the fact that they were God’s chosen people and nation, so they were bound to be alright weren’t they? Au contraire – “You alone have I intimately known of the families of the earth. That is why I shall punish you for all your wrong-doings (Amos3:2). As for my featured verse which portrays a much happier scenario, I had understood it in the past, along with some Reformed commentators to be referring to GOD’s justice and righteousness that would be flowing like an everlasting stream whereas  in the context it can only be His people’s. It refers to social justice and individual uprightness amongst a people who had been chosen and divinely instructed so as to be a light to the nations; the rest of the world whom God also wished to heal and, in due course bring to a fuller knowledge of His truth (1Tim2:4) by working from within through His chosen people. That interpretation is affirmed a few verses earlier (5:7) where Amos speaks of that same (human) justice  having been turned to bitterness and righteousness flung to the ground by God’s people who had “afflicted the just, taken bribes and oppressed the poor” (v12). Truly, this is why God was so often offended by His people in the Old Testament, not because they were “desperately trying to keep His Law through their own efforts” (as I once had interpreted Paul) but because they had forsaken the practice of His Law (i.e. being faithful to it by serving the one true God and caring for their neighbour and wider society, “for all the Law is fulfilled in ONE WORD, even in this; thou shalt LOVE thy neighbour as thyself” (Gal5:14 cf. Rom13:8).  These Israelites on the other hand were trusting in their status as God’s chosen nation; i.e. that they possessed the Law and often heard it read (so what?  – Rom2:13,14); they had been circumcised and observed the outward formalities of their religion (Am5:21-27). It was Amos’ task to convince them they had got it wrong – their privileged birth-right and knowledge of God’s Law only increased their culpability in the eyes of the One who Paul affirmed had been merciful towards “ignorant Gentiles” (Acts17:30) but was more stringent towards those He has chosen to act as His royal priesthood (Deut14:2, 1Pet2:9). As for the Church, it is one thing to long for Christ’s appearing, regrettably another to be entirely ready for it; that would seem to be a lesson from Amos.