I agree with that statement completely. However, that includes believing who Jesus is. If we dont believe that He is God incarnate we dont believe in Him and who He said He was.
Identification of the correct object in our belief/faith is indeed important. I suspect faith which is efficacious for salvation as recognized by God the Holy Spirit is adequate to accept Jesus Christ in His humanity providing that sacrifice.
On the other hand, if one adds to that faith the presumption of Christ as not being one with God, i.e. the second person of the Trinity, then that might be adequate grounds to void the faith as being misdirected to a different object than God Incarnate.
Complete and utter nonsense.
First of all, He never claimed to be God.
Secondly, the Thief on the Cross was saved and there is no indication at alll he believe Jesus was God or had teaching about the Trinity.
Honest Trintarians at least admit that the Thief knew nothing of the Trinity.