7:9 After these things I looked, and behold, a great multitude, which no one could count, from every nation and all tribes and peoples and tongues, standing before the throne and before the Lamb, clothed in white robes, and palm branches were in their hands;

After these things I looked,

These things probably are the six seals and the 144,000 Jews being sealed.

and behold, a great multitude, which no one could count,

The focus has changed from earth back to heaven because the THRONE and LAMB are here. The great multitude are believers (overcomers) from the Great Tribulation (verse 14) perhaps.

from

The expression "all peoples" is used in

John is given a glimpse of the fulfillment of Jesus words, Matthew 24:14. All the world hears it before the end comes; the Great Commission is completed (Acts 1:7-8).

STANDING before

CLOTHED in white robes (special reward) and palm branches were in their hands;

"Standing before" vs. "fallen down before" ... denotes a victory which is confirmed by the palm branches in their hands. These are ones who truly overcame the beast, antichrist, and martyrdom, and followed Christ even to death. They can hold their heads high in VICTORY!

This is a celebration like the Feast of Tabernacles, Leviticus 23:39-41. It is a joyful time (in heaven) especially after the 6 seals were opened (on earth). What the 'great multitude' must have endured (on earth) to get here (in heaven)! Truly, "O DEATH, where is your victory?" (1 Corinthians 15:54-57)