Standing (εστωτα). Second perfect active participle of ιστημ (intransitive). John resumes the picture in verse Revelation 10:2.

Lifted up (ηρεν). First aorist active indicative of αιρω, to lift up.

To heaven (εις τον ουρανον). Toward heaven, the customary gesture in taking a solemn oath (Genesis 14:22; Deuteronomy 32:40; Daniel 12:7).