The psalmist is describing an occasion of worship when his people were gathered to praise him at the temple. What ideas does the psalmist bring to our attention about the Lord that will help us to worship him as well?
The first theme that the psalmist mentions is the kingship of God and he does so by focusing on his throne. Where is his throne? According to verse 1, he sits enthroned upon the cherubim, which may cause us to think about a location in heaven. After all, the cherubim are a group of angelic beings. Yet it is more likely that the psalmist is thinking about the mercy seat on the ark of the covenant on which were placed models of the cherubim.
If that is the case, then we can see in what way the psalmist thought the Lord was great. The mercy seat was where the blood of the annual sacrifice on the Day of Atonement was sprinkled in order for the sins of Israel to be covered for a year. This is the distinctive feature of God. His mercy is what makes him great in the eyes of sinners because it reveals aspects of his wisdom, power and love that could not be known otherwise. Thankfully, the sacrifice of Jesus is not an annual event. Instead his sacrifice completely atoned for the sins of his people for ever and will not be repeated.
It was because of his mercy that the Lord had redeemed Israel from slavery in Egypt and brought them to the Promised Land; it was because of his mercy that the Lord had protected them from powerful opponents and given great victories over them. Therefore the people of God praised the Lord for his sovereignty which had been so gracious to them. They realised that he was superb and marked by splendour. The biblical term for this is holiness, which does not merely mean that he is detached from what is wrong. It also means that he is elevated in perfection above everything and everyone else. We know so much more about God than Israel ever did, so we should have far higher concepts of his holiness (v. 5).
At the same time, the psalmist realised that the King ruled in justice (v. 3). He requires his subjects to imitate him and react fairly to one another. Obviously, justice includes matters such as punishing wrongdoers and preventing sinful actions. Yet it involves more. To act fairly in a Christian sense is not to give to others what they deserve; instead it is to give to them what they need. Acting fairly and justly will mean that the poor will be provided for, that the hungry will be fed, and the lonely will be visited. After all, these are the criteria that Jesus will use when judging the world at the end of this age (Matt. 25:31-46).
The next theme to note is that the Lord delights to forgive (vv. 6-8). Even the great in Israel needed forgiveness and the psalmist recalls three leaders in particular: Moses, Aaron and Samuel. They served him at the tabernacle; there they had fellowship with God and received from him answers to prayer as well as divine instructions. Yet they were not perfect and not always wise. Sadly they committed sins that God chastised them for. Nevertheless he freely forgave them. As we gather in worship it is good for us to think about those we know whom God has forgiven all their sins. He has done so in a manner that has not compromised his holiness. Indeed, because he is a pardoning God, he is exalted greatly.