1 Peter 1:16 since it is written, “You shall be holy, for I am holy.”
Peter is quoting Leviticus 11:44-45 ESV 44 For I am the Lord your God. Consecrate yourselves therefore, and be holy, for I am holy. You shall not defile yourselves with any swarming thing that crawls on the ground. 45 For I am the Lord who brought you up out of the land of Egypt to be your God. You shall therefore be holy, for I am holy.”
Saying be holy does not indicate how to be holy since the word holy is an adjective which is a descriptor, indicating the condition of a person, place of thing.
Revelation 3:7 ESV
To the Church in Philadelphia
7 “And to the angel of the church in Philadelphia write: ‘The words of the holy one, the true one, who has the key of David, who opens and no one will shut, who shuts and no one opens.”
While Jesus never called Himself holy he did say “I am the way, the truth and the life.” Perhaps it is humility that kept Him from describing Himself as holy. But these are His words also: If you have seen me, you have seen the Father.
“He is the radiance of the glory of God and the exact imprint of his nature, and he upholds the universe by the word of his power.” Hebrews 1:3
Let us back up for a moment and examine Leviticus 11:44 and extract one word, consecrate. That is the secret to the how, the verb explains the adjective. Another way of saying that is to dedicate oneself in service to the will of God. He said not to defile ourselves.
Mark 7:15 There is nothing outside a person that by going into him can defile him, but the things that come out of a person are what defile him.
Jesus added: “What comes out of a person is what defiles him. For from within, out of the heart of man, come evil thoughts, sexual immorality, theft, murder, adultery, coveting, wickedness, deceit, sensuality, envy, slander, pride, foolishness. All these evil things come from within, and they defile a person.”
The condition of the heart is what truly matters. Give your heart to Jesus and become holy.
Acts 15:9 and he made no distinction between us and them, having cleansed their hearts by faith.
Consecrate yourself by being dedicated to His service.