Note 4 at Lk. 24:16: It is amazing that these two disciples, who were well-acquainted with what Jesus looked like, and were talking about Him at that very moment, didn't recognize Him. This same thing apparently happened to Peter and John with some other disciples at the Sea of Tiberias (Jn. 21:7,12).

In this instance, Mark 16:12 says that Jesus "appeared in another form" unto them. This was not another form in the sense that Jesus' physical appearance had changed. Jesus still had the nail prints in His feet and hands and the spear wound in His side (Jn. 20:27). Therefore, His physical features hadn't changed, but He now had a spiritual body (1 Cor. 15:44) which could only be spiritually discerned (1 Cor. 2:14). Jesus' spiritual body was visible to their physical eyes but only recognizable to their spiritual eyes.

Verse 15 reveals that they were not operating from their spirits, but were reasoning in their minds (Rom. 8:6). This is what blinded their eyes that they should not know Him.

Likewise, Jesus is always with us (Heb. 13:5) but we often fail to recognize His presence with us because we are blinded by our carnal minds (Eph. 4:18).