The Promise of Victory and the Command to turn away from Idolators

Allah says,

وَلَقَدْ سَبَقَتْ كَلِمَتُنَا لِعِبَادِنَا الْمُرْسَلِينَ ﴿١٧١﴾

And, verily, Our Word has gone forth of old for Our servants, the Messengers,

meaning, it has already been stated in the first decree that the Messengers and their followers will ultimately prevail in this world and the Hereafter.

This is like the Ayah:

كَتَبَ اللَّهُ لاّغْلِبَنَّ أَنَاْ وَرُسُلِى إِنَّ اللَّهَ قَوِىٌّ عَزِيزٌ

Allah has decreed: "Verily, it is I and My Messengers who shall be the victorious.''

Verily, Allah is All-Powerful, Almighty. (58:21)

and,

إِنَّا لَنَنصُرُ رُسُلَنَا وَالَّذِينَ ءَامَنُواْ فِى الْحَيَوةِ الدُّنْيَا وَيَوْمَ يَقُومُ الاٌّشْهَـدُ

Verily, We will indeed make victorious Our Messengers and those who believe in this world's life and on the Day when the witnesses will stand forth. (40:51)

وَلَقَدْ سَبَقَتْ كَلِمَتُنَا لِعِبَادِنَا الْمُرْسَلِينَ