No, it's not true. Here are examples of ECFs teaching about salvation by grace through faith (aka our assurance of salvation).
It is indeed proper to God, and befitting His character, to show mercy and pity, and to bring salvation to His creatures, even though they be brought under danger of destruction. “For with Him,” says the Scripture, “is propitiation.”
Do we believe as Irenaeus did in what Scripture says?
Let us attend to what is good, pleasing, and acceptable in the sight of Him who formed us. Let us look stedfastly to the blood of Christ, and see how precious that blood is to God,35 which, having been shed for our salvation, has set the grace of repentance before the whole world.
-Clement of Rome-
Look to blood of Christ and know it is precious.
Let my spirit be counted as nothing for the sake of the cross, which is a stumbling-block to those that do not believe, but to us salvation and life eternal.
My spirit, my work, my deeds be counted as nothing, like Paul said. Ahh, but the cross has been and always will be a stumbling block. But to those who believe, it is, nay Christ is salvation and life eternal.
And I answered, “Attend to me, I beseech you, while I speak of the statement which the Holy Spirit gave utterance to in this Psalm; and you shall know that I speak not sinfully, and that we2225 are not really bewitched; for so you shall be enabled of yourselves to understand many other statements made by the Holy Spirit. ‘Sing unto the Lord a new song; sing unto the Lord, all the earth: sing unto the Lord, and bless His name; show forth His salvation from day to day, His wonderful works among all people.’ He bids the inhabitants of all the earth, who have known the mystery of this salvation, i.e., the suffering of Christ, by which He saved them, sing and give praises to God the Father of all things, and recognise that He is to be praised and feared, and that He is the Maker of heaven and earth, who effected this salvation in behalf of the human race, who also was crucified and was dead, and who was deemed worthy by Him (God) to reign over all the earth.
-Justin the Martyr-
In all of these texts is the thought that it is God who saves those who believe Him through the work of Christ Jesus.