Adventist’s will often quote Matthew 5:48 to support the idea that sinless perfectionism is required to be saved. In their minds, the verse could be understood to be saying “be perfect as your father in Heaven is perfect if you want to be saved and reconciled to God.” This is incorrect.
This verse is a part of the larger Sermon on the Mount. In Matthew 5 He is expounding upon the Law and showing the hearer how far they fall short of the standard. If you keep reading into the next two chapters, Jesus transitions into the Gospel, which is the good news for sinners regarding their sin and need for a savior.
The Seventh-Day Adventist Church doesn’t properly understand what is called the Law Gospel distinction in the scriptures. The Law is anything in scripture that has to do with commands or prohibitions. The Gospel is anything in scripture pertaining to justification, salvation, reconciliation, and the mercy of God. Both have a place and function in the Christians life. It is by the Gospel that we are saved, not by the Law. The Law convicts the sinner of sin, showing them their need for a savior, thus pointing them to the Gospel where they find forgiveness and reconciliation.
Jesus is simply revealing to sinners how far they fall short in Matthew 5:48, not how they can be reconciled to God and saved. He explains this later when transitioning into the Gospel.