“Then said they unto him, What shall we do, that we might work the works of God? Jesus answered and said unto them, This is the work of God, that ye believe on him whom he hath sent.” John 6:28-29
Faith is certainly the requirement, however, whent he process of sorting out who is saved and who is condemned, it is done according to people's works of love.
[31] And when the Son of man shall come in his majesty, and all the angels with him, then shall he sit upon the seat of his majesty. [32] And all nations shall be gathered together before him, and he shall separate them one from another, as the shepherd separateth the sheep from the goats: [33] And he shall set the sheep on his right hand, but the goats on his left. [34] Then shall the king say to them that shall be on his right hand: Come, ye blessed of my Father, possess you the kingdom prepared for you from the foundation of the world. [35] For I was hungry, and you gave me to eat; I was thirsty, and you gave me to drink; I was a stranger, and you took me in:[36] Naked, and you covered me: sick, and you visited me: I was in prison, and you came to me. [37] Then shall the just answer him, saying: Lord, when did we see thee hungry, and fed thee; thirsty, and gave thee drink? [38] And when did we see thee a stranger, and took thee in? or naked, and covered thee? [39] Or when did we see thee sick or in prison, and came to thee? [40] And the king answering, shall say to them: Amen I say to you, as long as you did it to one of these my least brethren, you did it to me.
[41] Then he shall say to them also that shall be on his left hand: Depart from me, you cursed, into everlasting fire which was prepared for the devil and his angels. [42] For I was hungry, and you gave me not to eat: I was thirsty, and you gave me not to drink. [43] I was a stranger, and you took me not in: naked, and you covered me not: sick and in prison, and you did not visit me. [44] Then they also shall answer him, saying: Lord, when did we see thee hungry, or thirsty, or a stranger, or naked, or sick, or in prison, and did not minister to thee? [45] Then he shall answer them, saying: Amen I say to you, as long as you did it not to one of these least, neither did you do it to me.
[46] And these shall go into everlasting punishment: but the just, into life everlasting.
(matthew 25)
That is becasue, as the scripture teaches,
[17] So faith also, if it have not works, is dead in itself. [18] But some man will say: Thou hast faith, and I have works: shew me thy faith without works; and I will shew thee, by works, my faith. [19] Thou believest that there is one God. Thou dost well: the devils also believe and tremble. [20] But wilt thou know, O vain man, that faith without works is dead?[21] Was not Abraham our father justified by works, offering up Isaac his son upon the altar? [22] Seest thou, that faith did co-operate with his works; and by works faith was made perfect? [23] And the scripture was fulfilled, saying: Abraham believed God, and it was reputed to him to justice, and he was called the friend of God. [24] Do you see that by works a man is justified; and not by faith only? [25] And in like manner also Rahab the harlot, was not she justified by works, receiving the messengers, and sending them out another way?
[26] For even as the body without the spirit is dead; so also faith without works is dead.
(James 2)
Protestantism is a damnable and heretical sect for that reason more that for what they "think" about the Purgatory, by the way.