Tafsir Ibn Abbas: Ibrahim, Ayah 46

And verily they plotted against the Prophet s their plot — when they desired to kill him or detain him in his house or banish him — but their plotting is with God that is to say knowledge or the requital thereof is with God and their plotting even though it be great was not such whereby mountains should be moved meaning that it is not of any importance but that they are only harming themselves thereby. It is said that the use of ‘mountains’ here is meant to be literal; alternatively it is also said to be a reference to the laws of Islam which are likened to these mountains in the way that they are established and fixed a variant reading has la-tazūlu instead of li-tazūla with in softened from inna ‘verily’ in which case the intended meaning is that the extent of their plotting is great. It is said that ‘plotting’ here is actually a reference to their unbelief. This second reading is consonant with God’s saying Whereby the heavens are almost torn and the earth split asunder and the mountains fall crashing Q. 1990; according to the former reading however one should read it as if it were wa-mā kāna and their plotting was not such ….