'Adhere to righteousness even though you will not be able to do all the good acts
It was narrated that Thawban, may Allah be pleased with him, said:
"The Messenger of Allah, may the peace and blessings of Allah be upon him, said: 'Adhere to righteousness even though you will not be able to do all the good acts. Know that the best of your deeds is the prayer and that none but a believer maintains his state of ablution.'"
steadfastness is the obedience to the command of Allah the Almighty, sticking to the right path, and rectifying oneself whenever deviates from the right path, or followed his inclination. The critical point concerning steadfastness is that one should have a sound intention in all acts especially he seeks other than Allah with his dead mainly if he likes showing off.
The Prophet (peace and blessings of Allah be upon him) commanded his companions and those who will come after them to stick to righteousness; because this is the best commandment he received from his Lord Almighty in The Quran. Allah says (interpretation of the meaning):
{So remain on a right course as you have been commanded, [you] and those who have turned back with you [to Allah ], and do not transgress. Indeed, He is Seeing of what you do}
Quran (11:112)
This verse was the most severe verse received by the Prophet (peace and blessings of Allah be upon him) from his Lord the Almighty. His heart showed reverence to it, and he fully understood and applied it. His companions emulated him so they were of perfect manners.