This incident reminds me of Exodus 14:16 when Moses parted the Red Sea for Israel to pass safely through its waters to the other side (cf. Isaiah 43:15-16), but, when Pharaoh’s army tried to follow, they perished as the walls of the sea came crashing down upon them like the powerful waters of a great flood (Exodus 14:26; cf. Nehemiah 9:11). Nevertheless, if God parted the waters of the Red Sea and made a way through them for his people to safely cross, how would this apply (if at all) to the heavens parting just after John baptized Jesus?
First of all, it means access to heaven has been opened to man in the person of Jesus. Stephen saw the man, Jesus, in heaven standing at the right hand of God—the position of the promised Messiah (cf. Acts 7:56). Secondly, it shows that Jesus can manifest himself to man as easily in vision (Luke 24:31) as in spirit, i.e. through the indwelling of the Holy Spirit (John 14:21-23). Thirdly, not only had the heavens opened, but the Greek shows they stand open (John 1:51), revealing the Way through the heavens to the Father (John 14:6; cf. Isaiah 43:15-16). Finally, the Gospel is made manifest to others through the power of God in men’s preaching (2Corinthians 2:14; cf. Exodus 14:16), but, at the same time, this same Gospel is hidden from those who mind the things of the flesh (2Corinthians 3:14; cf. Exodus 14:26).
One may say that this sounds good, but Israel actually passed through the Red Sea (1Corinthians 10:1). How have we passed through the heavens, if, indeed, they have been parted before us? We are **in** Christ similar to how a babe is **in** its mother’s womb. We are of God ‘in’ Christ, and he has become our wisdom, our righteousness, our sanctification and our redemption (1Corinthians 1:30). Whatever happens to Jesus, happens to those who are in him, just as whatever occurs to a pregnant woman happens also to the babe within her. If she travels from Philadelphia to Seattle, so does the babe within her. Therefore, because Jesus was rescued from the grave, so have we been rescued, because we are in him. Because Jesus has ascended into the heavens (Acts 1:9-11), so we who are in him have also passed through the heavens to be seated in heavenly places in him (Ephesians 2:6).
Therefore, Jesus has brought eternal life to light for us through his resurrection (2Timothy 2:10). The Scripture says: in Adam (i.e. in the flesh) all die, but in Christ (i.e. in the Spirit) all are made alive (1Corinthians 15:22); and when he shall appear from the heavens, we shall appear with him in glory (Colossians 3:4). Although it is not certain what we shall be like, we know we shall be like him, because we shall see him as he is (cf. 1John 3:1-2).
Immediately afterward the Holy Spirit descended upon Jesus, and a voice from heaven was heard to say: “This is my beloved Son, in whom I am well pleased.” It appears that Jesus was anointed by God at this time for the task before him (cf. Luke 4:18 and Acts 10:38). At the parting of the heavens, Jesus became the Messiah or the Anointed of God (cf. Psalm 2:1-2; Acts 4:27; cf. Acts 4:5-8) and embarked from this point to fulfill the task for which he was sent (Psalm 68:18; cf. Luke 4:18-20; Ephesians 4:8; Isaiah 64:1).
 According to Robertson’s Word Pictures and Vine’s Word Studies the Greek verb anoigo (G455 – ‘opened’ at John 1:51 in the KJV) is in the perfect participle active. This reveals a condition that remains true after the completed act. That is, the state of the opening of the heavens remained true after they were opened by God. The heavens weren’t closed afterward.