1 Enoch 61:2
1 And I saw in those days how long cords were given to those angels, and they took to themselves wings and flew, heading north. 2 I asked the angel, 'Why have those angels taken these cords and departed?' And he replied, 'They have gone to measure.' 3 The angel who accompanied me said, 'These shall bring the measures of the righteous, and the ropes of the righteous to the righteous, that they may rely on the name of the Lord of Spirits forever and ever.' 4 The chosen will begin to dwell with the chosen, and these are the measures which shall be given to faith and which shall strengthen righteousness.
Revelation 21:15
15 The angel who spoke to me had a golden measuring rod with which to measure the city and its foundation stones and wall. 16 Now the city is laid out as a square, its length and width the same. He measured the city with the measuring rod at 1,400 miles (its length and width and height are equal). 17 He also measured its wall, 144 cubits according to human measurement, which is also the angel’s.
Notes and References
"... The significance of the measuring means that their salvation is secured, despite physical harm. This is a further development of the ‘sealing’ of 7:2–8 and is consistent with 1 Enoch 61:1–5, where the angelic ‘measuring’ of the righteous elect ensures that their faith will be strengthened and not demolished, despite the fact that their bodies will be destroyed. In the Old Testament generally, ‘measuring’ was metaphorical for a decree of protection ... An angel measuring various features of the temple complex in Ezekiel 40–48 metaphorically pictures the sure establishment and subsequent protection of the temple. In Revelation 21:15–17 an angel, also in dependence on the same Ezekiel text, ‘measures with a reed’ (metreō + kalamos, as in 11:1) ‘the city and its gates and its wall’. There the measuring of the city and its parts pictures the security of its inhabitants against the harm and contamination of unclean and deceptive people ..."
Beale, G. K. The Temple and the Church’s Mission: A Biblical Theology of the Dwelling Place of God (p. 387) InterVarsity Press, 2004