Hussain's passionate plea
England endured a gruelling final three days in the field in the drawn third Test which ended at Kingsmead on Thursday, and just three days later they will again attempt to square a five-match series that South Africa currently lead 1-0.
The extent of their weariness showed when England cancelled their planned practice session at Newlands this morning.
"Inner strength must come through and people must dig deep, that's what we're here for," Hussain said. "It's amazing what you can find within yourself when there's something like a millennium Test in Cape Town up for grabs.
"The spirit in our dressingroom after the Kingsmead Test was not of a side that was down, it was of a side looking forward to the next game."
Hussain was confident his men would be up to the task of fielding first at Newlands, which will be likely if South Africa win the toss on what has proved a dependable batting pitch in recent seasons.
"If we end up in the field for two days I'd expect the team to be just like they have been in the last two days in the field, that is not to throw the towel in and to try and bowl the opposition out.
"People won't be left out because they might have tired legs. Our best bowlers for the particular wicket we see in Cape Town will be picked.
"We're quite pleased with the way we are at the moment. We've done some hard work and we'll carry on doing it."
South Africa staved off defeat at Kingsmead despite being asked to follow on for the first time in 73 Tests, and going into the final day just 41 runs ahead with four wickets down.
Much of the credit for the successful rescue effort went to opener Gary Kirsten, whose 275 equalled the highest Test innings by a South African.
South African captain Hansie Cronje said his team had been steeled by the experience.
"It was important for us to get through that situation," Cronje said. "We were under pressure because we hadn't been there before, so our confidence is certainly boosted."
Kirsten expected another sound batting pitch at Newlands, his home ground.
"The wicket hasn't bounced as much as it did last season, so unless they leave grass on it I think it'll be a good pitch," Kirsten said. "It's played very well this season with even bounce, a very good batting wicket."
South Africa have named an unchanged 12 for the fourth Test, with controversially axed batsman Jonty Rhodes expected to return at the expense of paceman Mornantau Hayward.
England were not due to announce their squad today, but left-arm fast bowler Alan Mullally and batsman Michael Vaughan were said to have recovered from injuries.
Mullally's selection could add variety to an England attack which, in Hussain's own words, "lacks penetration" on flatter surfaces.