Cyril of Jerusalem

For in the power of the Holy Spirit, by the will of the Father and the Son, Peter stood with the Eleven and, lifting up his voice (according to the text, "Lift up your voice with strength, you who bring good tidings to Jerusalem"), captured in the spiritual net of his words about three thousand souls. So great was the grace that worked in all the apostles together, that, out of the Jews … this great number believed, were baptized in the name of Christ and continued steadfast in the apostles' doctrine and in the prayers.

Catechetical Lecture 17:21 ↗

Ambrose of Milan

Therefore, let us transcend the works of the world, so that we may be able to see God face to face. Ascend to the mountain that proclaims Zion. If the one who proclaims Zion ascends to the mountain, how much more the one who proclaims Christ and the risen Christ? Perhaps many will see him in the body; for we have known Christ according to the flesh: but now we no longer know him.

Commentary on Luke, Book 7 ↗

Jerome

Ascend to the high mountain, you who bring good news to Zion; lift up your voice with strength, you who bring good news to Jerusalem. Lift it up, do not fear; say to the cities of Judah, 'Here is your God!' See, the Lord God comes with might, and His arm rules for Him. See, His reward is with Him, and His recompense accompanies Him. He tends His flock like a shepherd; He gathers the lambs in His arms and carries them close to His heart; He gently leads the nursing ewes. …

Commentary on Isaiah ↗

Gregory the Dialogist

If the Lord admonishes a prophet to rise, does he dare to preach the Lord who lies fallen through the lapse of wickedness? For this is why every preacher is commanded through Isaiah: "Go up onto a high mountain, you who evangelize Zion" (Isa. 40:9). The high mountain is the perfection of teaching and of works. Let him therefore rise who is commanded to anoint the king; let him stretch himself toward lofty things. …

Commentary on 1 Kings, Book 6, Chapter 3 ↗