Allah mentions the descriptions of the liars who falsely claim faith with their lips, while faith is not firm in their hearts. When a test or trial comes in this world, they think that this is a punishment from Allah, so they leave Islam. Allah says:

Ibn 'Abbas said, “Meaning that their trial is leaving Islam if they are made to suffer for Allah.” This was also the view of others among the Salaf. This Ayah is like the Ayah,

{And among mankind is he who worships Allah as it were upon the edge: if good befalls him, he is content therewith; but if a trial befalls him, he turns back on his face...} until:

{That is a straying far away} (22:11-12).
Then Allah says:

meaning, “if victory comes from your Lord, O Muhammad, and there are spoils of war, these people will say to you, 'We were with you,' i.e., we are your brothers in faith.” This is like the Ayat

{Those who wait and watch about you; if you gain a victory from Allah, they say: "Were we not with you?" But if the disbelievers gain a success, they say (to them): "Did we not gain mastery over you and did we not protect you from the believers?"} (4:141).

{Perhaps Allah may bring a victory or a decision according to His will. Then they will become regretful for what they have been keeping as a secret in themselves} (5:52).

And Allah tells us about them here:

Then Allah says:

meaning, 'does Allah not know best what is in their hearts and what they store secretly within themselves, even though outwardly they may appear to be in agreement with you?'

Allah will test the people with calamities and with times of ease, so that He may distinguish the believers from the hypocrites, to see who will obey Allah both in times of hardship and of ease, and who will obey Him only when things are going in accordance with their desires. As Allah says:

{And surely, We shall try you till We test those who strive hard and the patient, and We shall test your facts.} (47:31)

After the battle of Uhud, with its trials and tribulations for the Muslims, Allah said:

[Wait, page cuts to “{And no friend will ask a friend (about his condition)...”]
{And no friend will ask a friend (about his condition), though they shall be made to see one another} (70:10-11).

Here Allah tells us that those who call others to disbelief and misguidance will, on the Day of Resurrection, bear their own sins and the sins of others, because of the people they misguided. Yet that will not detract from the burden of those other people in the slightest, as Allah says:

{That they may bear their own burdens in full on the Day of Resurrection, and also of the burdens of those whom they misled without knowledge} (16:25).

In the Sahih, it says:

«Whoever calls others to true guidance, will have a reward like that of those who follow him until the Day of Resurrection, without it detracting from their reward in the slightest. Whoever calls others to misguidance, will have a burden of sin like that of those who follow him until the Day of Resurrection, without it detracting from their burden in the slightest.»

In the Sahih, it also says:

«No person is killed unlawfully, but a share of the guilt will be upon the first son of Adam, because he was the first one to initiate the idea of killing another.»