en_tn_condensed/rev/19/10.md

I fell down at his feet

This means that John purposely lay on the ground and stretched himself out in reverence or submission. This action was an important part of worship, to show respect and willingness to serve. See how you translated "fell down" in Revelation 5:8.

your brothers

The word "brothers" here refers to all believers, male and female.

who hold the testimony about Jesus

Here holding stands for believing in or announcing. Alternate translation: "who speak the truth about Jesus" (See: rc://en/ta/man/translate/figs-metaphor)

for the testimony about Jesus is the spirit of prophecy

Here "spirit of prophecy" refers to God's Holy Spirit. Alternate translation: "for it is the Spirit of God who gives people the power to speak the truth about Jesus" (See: rc://en/ta/man/translate/figs-explicit)