Then the devil took him to the holy city and set him on the pinnacle of the temple and said to him, “If you are the Son of God, throw yourself down, for it is written, “‘He will command his angels concerning you,’ and “‘On their hands they will bear you up lest you strike your foot against a stone.’” (Matthew 4:5-6 ESV)What the Devil says here is just a small portion of Psalm 91 but there's nothing within Psalm 91 that explicitly states that Psalm 91 is about the Son of God. But Devil seemed to realize that Psalm 91 is primarily about the Son of God. According to the Devil if Jesus truly is the Son of God then Psalm 91 is about Jesus. Certainly the Devil takes these words out of context as is shown by Jesus' refusal to throw Himself down, but Jesus doesn't deny the basic premise that Psalm 91 is primarily about the Son of God. Because of our union with Christ we also can take the words of Psalm 91 upon our lips. But Psalm 91 first and foremost is about Christ Himself.
Both the Devil and Jesus knew that the Old Testament Scriptures were all about the Son of God. The Devil made no attempt to convince Jesus that the Old Testament was just about morality or random history lessons. Jesus knew the Scriptures too well to be convinced by such nonsense. Instead, the Devil tries to keep Jesus from the cross by getting Him to put on a spectacular display to prove He is the Son of God. Certainly many would have believed that Jesus was the Messiah if they saw Him jump from the top of the temple and a bunch of angels catching Him.
But both the Devil and Jesus knew that the Scriptures are all about Jesus. After the resurrection, the Apostles all realized that the Scriptures were all about Jesus. Matthew doesn't have any problem taking a statement from Hosea 11:1 about what God had done for Israel and interpreting it as a prophecy about Jesus. The early church fathers understood that the Scriptures were all about Jesus. Despite all the error that had crept into the church over time, you cannot find a pre-Reformation Christian commentary on the Psalms that doesn't interpret them as being all about Jesus. But starting with Calvin, many Protestants were deceived into thinking that some Psalms are Messianic while others are not. In reaction to some of the fanciful allegorical interpretations of the past, many Protestants a method of Biblical interpretation claimed to have greater objectivity. The end result is a method of interpretation which had not existed before and one that actually forbids the very kind of Biblical interpretation that we find the Apostle's engaging in. Matthew 2:15 takes a statement about a past event concerning Israel and interprets it as a prophecy about Jesus. But Matthew would fail a Biblical interpretation class if he tried to do this kind of thing today in a Protestant seminary.
There are reasons to be skeptical about what some would regard as allegorical interpretations of Scripture. Left to our own devices we can make the Bible say just about anything that we want it to. But we have been given the key to the Scriptures by Jesus Himself. Jesus says the Scriptures are all about Jesus. Any system of interpretation that does not find Jesus in every passage must be rejected. As we see in Harold Camping, you can certainly allegorize the Scriptures in such a way that Jesus becomes little more than a footnote. But the same holds true for those who adhere to the Historical-Grammatical method. If the Scriptures are understood to be the icon of Jesus then we interpret them correctly. But if we attempt to stand outside of the Scriptures and interpret them in a completely objective manner we will end up reading the Scriptures in the same way many of the Jews did in Jesus' day.
The Devil did not dare to try to convince Jesus that all the Scriptures are not about Jesus. In the middle ages the Devil caused a shift in focus from what Jesus did to what we need to do for Jesus but there was no outright denial that the Scriptures were all about Jesus. It really wasn't until the Reformation that the Devil managed to convince some in the church that faithfulness to the Scriptures required a person to believe that some of the Scriptures are not really about Jesus. The Devil would loves it when we diligently study the Scriptures and think they are about something other than Jesus.