Isaiah 40:4
Every valley shall be exalted, and every mountain and hill shall be made low: and the crooked shall be made straight, and the rough places plain:
Torrey's Topical Textbook—AKJV

Zechariah 4:7
Who are you, O great mountain? before Zerubbabel you shall become a plain: and he shall bring forth the headstone thereof with shoutings, crying, Grace, grace to it.
Torrey's Topical Textbook—AKJV

Matthew 17:20
And Jesus said to them, Because of your unbelief: for truly I say to you, If you have faith as a grain of mustard seed, you shall say to this mountain, Remove hence to yonder place; and it shall remove; and nothing shall be impossible to you.
Torrey's Topical Textbook—AKJV