What made Simeon recognize that the perfectly ordinary infant boy was the promised Messiah?
First, he was righteous and devout. That means he was in right standing with God. His relationship with God was excellent. He was devoted to the Lord, meaning that his most intimate thoughts and all his actions centered on God - not man.
Second, he was moved by the spirit. We're talking about the Holy Spirit here. Before Christ's death and resurrection, the Spirit of God moved upon people from time to time. They did not have the indwelling Paraclete that Jesus sent to His followers.
But evidently Simeon was familiar with the promptings of the Holy Spirit. He was "tuned in" to those leadings. And when he saw the Child, he recognized Him as the promised Salvation.
We can be righteous and devout as Simeon was. It requires that we stay in tune with God and His Holy Spirit. Reading His word on a daily basis is a good starting point. Thinking on His words and repeating them to ourselves deepens our understanding of His ways.
When we center our lives on Him, we have the hope of eternal joy through His Son, Jesus Christ. Without Christ, we are all lost. With Him we have eternal life.
Keep us ever close to You. Strengthen us in Your word that we may be totally focused upon You and Your will in our lives. Help us to recognize the blessing and miracles as You bestow them.
In Jesus' most precious name.