John described the Lamb in ways that Psalm 2 described a certain king. This was the king that God chose to be the son of God.
Other kings, nations and rulers on earth tried to be more powerful than God. But God’s son ruled from Mount Zion as king over all other rulers. Mount Zion was another name for Mount Moriah.
The Lamb that John saw standing on Mount Zion was this king from Psalm 2. The two beasts in Revelation chapter 13 were like the rulers that opposed God in Psalm 2. The Lamb was joined by his faithful followers. They worshipped him with a new song. This was a way to celebrate Jesus’ work of rescuing them from evil.
Being marked with Jesus’ name and the Father’s name showed that they belonged to Jesus. John had seen the crowd of 144,000 people before. They were a sign of all the people throughout history who are God’s faithful people. That’s what it meant that they were a first offering.