allah, the exalted, says:

"(and the man who believed said:) `... and my affair i leave it to allah. verily, allah is the all-seer of (his) slaves.' so allah saved him from the evils that they plotted (against him)". (40:44,45)

440. abu hurairah (may allah be pleased with him) reported: messenger of allah (pbuh) said, "allah says: `i am just as my slave thinks of me when he remembers me.' by allah! allah is more pleased with the repentance of his slave than one of you who unexpectedly finds in the desert his lost camel. `he who comes closer to me one span, i come closer to him a cubit; and he who comes closer to me a cubit, i come closer to him a fathom; and if he comes to me walking, i come to him running".
[al-bukhari and muslim].

commentary: this hadith highlights the merits of expecting good treatment of allah. but this has to be backed by good actions, in the same way as one can hope for good results after ploughing and sowing seeds. it is obvious that one who accomplishes good deeds will expect good consequences, and one who does evil deeds will expect evil consequences. allah will treat people according to their expectation that are founded on their actions, and the reward will match their deeds.

441. jabir bin `abdullah (may allah be pleased with him) reported: i heard the prophet (pbuh) saying three days before his death: "let none of you die unless he has good expectations from allah".
[muslim].

commentary:  this hadith also tells us that one should always perform good deeds because no one knows the time of his death. at the time of death one must entertain hope for allah's pardon and mercy which cannot be possible without good actions. thus, this hadith conveys the same meanings of the following ayah:

"and die not except in a state of islam (as muslims)". (3:102).

442. anas (may allah be pleased with him) reported: messenger of allah (pbuh) said, "allah, the exalted, has said: `o son of adam, i forgive you as long as you pray to me and hope for my forgiveness, whatever sins you have committed. o son of  'adam, i do not care if your sins reach the height of the heaven, then you ask for my forgiveness, i would forgive you. o son of  'adam, if you come to me with an earth load of sins, and meet me associating nothing to me, i would match it with an earthload of forgiveness.'''
[at-tirmidhi].

commentary:
1. what it really means is that if sins of a muslim, committed in ignorance and carelessness, become so numerous that in stacks touch the heights of skies, he should not lose hope in allah's mercy. if he repents wholeheartedly for his sins, makes penitence for them and begs allah's forgiveness, he will certainly find allah's mercy open for him.

2. shirk (polytheism) is an absolutely unpardonable sin. all other sins, how many and how grave they may be, can be forgiven by allah. he will pardon them if he likes and send the sinful persons straight to jannah, or keep them for a while in hell and then shift them to jannah. in any case, the punishment of hell will not be eternal for them, as it is for the mushriks (polytheist).