KJV: 43 And there appeared an angel unto him from heaven, strengthening him. 44 And being in an agony he prayed more earnestly: and his sweat was as it were great drops of blood falling down to the ground.
NIV: 43 An angel from heaven appeared to him and strengthened him. 44 And being in anguish, he prayed more earnestly, and his sweat was like drops of blood falling to the ground.
ESV: 43 And there appeared to him an angel from heaven, strengthening him. 44 And being in agony he prayed more earnestly; and his sweat became like great drops of blood falling down to the ground.
CSB: 43 Then an angel from heaven appeared to him, strengthening him. 44 Being in anguish, he prayed more fervently, and his sweat became like drops of blood falling to the ground.
External evidence
External evidence suggests they are additions (P75 א1 A B, and other manuscripts include marks indicating their inauthenticity).
Internal evidence
These verses are suspected as being additions but modern translations include them. The NASB footnote says, “Most early mss do not contain vv 43 and 44, and the NRSV and NET bracket the verses. NA also brackets the verses but leaves them in the text because they are an early addition (as seen in the Patristic citations and allusions). The fact that they are also placed after Matthew 26:39 argues for their inauthenticity.
UBS gives the omission of the words an A rating.