PROPHET MUHAMMAD (ﷺ) said:
No worshipper has ever said:

sincerely, except that the gates of heaven are opened for it, until it reaches to the Throne, so long as he avoids the major sins.

TRANSLATION:
None has the right to be worshipped but Allah

PROPHET MUHAMMAD (ﷺ) said:
Whoever says:

ONE HUNDRED times a day, will be forgiven all his sins even if they were as much as the foam of the sea.

TRANSLATION:
Glory is to Allah and the praise

PROPHET MUHAMMAD (ﷺ) said:
There are two expressions which are very easy for the tongue to say, but they are very heavy in the balance and are very dear to The Beneficent (Allah), and they are,

TRANSLATION:
Glory is to Allah, the Magnificient; Glory is to Allah and the praise.

It was narrated from Juwayriyah that the Prophet (ﷺ) left her one morning when he (ﷺ) prayed Subh, (i.e., Fajr prayer) and she was in her prayer-place, then he (ﷺ) came back after the forenoon had come, and she was still sitting there. He (ﷺ) said: Are you still as you were when I left you?’ She said: Yes. The Prophet (ﷺ) said: After I left you I said four words THREE times, which if they were weighed against what you have said today, they would outweigh it:

Glory and praise is to Allah,
1) As much as the number of His creation,
2) As much as pleases Him,
3) As much as the weight of His Throne and
4) As much as the ink of His words.

PROPHET MUHAMMAD (ﷺ) said:
Whoever says:

then Allah will forgive him, even if he fled from battle.

TRANSLATION:
I seek forgiveness from Allah, the Magnificent, whom there is none worthy of worship but Him, the Living, Al-Qayyum, and I repent to him.

PROPHET MUHAMMAD (ﷺ) said:
Whoever says:

ONE HUNDRED times will get the same reward
1) As given for manumitting (freeing) ten slaves;
2) And one hundred good deeds will be written in his accounts,
3) And one hundred sins will be deducted from his accounts,
4) And it (his saying) will be a shield for him from Satan on that day till night,
5) And nobody will be able to do a better deed except the one who does more than he.

NOTE : In Hadith of Sahih Muslim, it is mentioned freeing 100 slaves.