Merriam -Webster defines impeccable as "not capable of sinning or liable to sin". The question then arises, how are we to understand the following verse? -
"For in that he himself hath suffered being tempted, he is able to succour them that are tempted." (Heb 2:18 KJV)
The NRSV translates it "tested" rather than "tempted"; and the Revised English Bible translates "Because he himself has passed through the test of suffering, he is able to help those who are in the midst of their test. (Heb 2:18 REB)
I hold to a highly pure view of Jesus Christ in that He had no inner sin nature to which the temptation could attach itself, so he could not sin. Merriam-Webster defines tempt as "to entice to do wrong by promise of pleasure or gain". There is another verse to consider on this -
"Let no man say when he is tempted, I am tempted of God: for God cannot be tempted with evil, neither tempteth he any man:" (Jas 1:13 KJV)
On James 1:13 the NRSV and REB keep to the word "tempt" rather than "test".
Orthodox Christianity insists upon the impeccability of Jesus Christ. The Chalcedonian Creed (451 AD) established the orthodox view that Christ has two natures (human and divine) that are unified in one person.
"We, then, following the holy Fathers, all with one consent, teach men to confess one and the same Son, our Lord Jesus Christ, the same perfect in Godhead and also perfect in manhood; truly God and truly man, of a reasonable [rational] soul and body; consubstantial [co-essential] with the Father according to the Godhead, and consubstantial with us according to the Manhood; in all things like unto us, without sin; begotten before all ages of the Father according to the Godhead, and in these latter days, for us and for our salvation, born of the Virgin Mary, the Mother of God, according to the Manhood; one and the same Christ, Son, Lord, only begotten, to be acknowledged in two natures, inconfusedly, unchangeably, indivisibly, inseparably; the distinction of natures being by no means taken away by the union, but rather the property of each nature being preserved, and concurring in one Person and one Subsistence, not parted or divided into two persons, but one and the same Son, and only begotten, God the Word, the Lord Jesus Christ; as the prophets from the beginning [have declared] concerning Him, and the Lord Jesus Christ Himself has taught us, and the Creed of the holy Fathers has handed down to us."
To say Jesus Christ had to be capable of sinning in order to be tempted as we are would require the belief that Jesus Christ inherited the sin nature from Adam, which he did not, Romans 5.
The NRSV and REB change to test is the better understanding of Hebrews 2:18. I believe to deny the impeccability of Jesus Christ drags one into a blasphemous system of belief.