From the Explanations of the Psalms by Saint Ambrose, bishop
(Ps. 36, 65-66: CSEL 64, 123-125)
Open your lips, and let God’s word be heard
We must always meditate on God’s wisdom, keeping it in our hearts and on our lips. Your tongue must speak justice, the law of God must be in your heart. Hence Scripture tells you: You shall speak of these commandments when you sit in your house, and when you walk along the way, and when you lie down, and when you get up. Let us then speak of the Lord Jesus, for he is wisdom, he is the word, the Word indeed of God.
It is also written: Open your lips, and let God’s word be heard. God’s word is uttered by those who repeat Christ’s teaching and meditate on his sayings. Let us always speak this word. When we speak about wisdom, we are speaking of Christ. When we speak about justice, we are speaking of Christ. When we speak about peace, we are speaking of Christ. When we speak about truth and life and redemption, we are speaking of Christ.
Open your lips, says Scripture, and let God’s word be heard. It is for you to open, it is for him to be heard. So David said: I shall hear what the Lord says in me. The very Son of God says: Open your lips, and I will fill them. Not all can attain to the perfection of wisdom as Solomon or Daniel did, but the spirit of wisdom is poured out on all according to their capacity, that is, on all the faithful. If you believe, you have the spirit of wisdom.
Meditate, then, at all times on the things of God, and speak the things of God, when you sit in your house. By house we can understand the Church, or the secret place within us, so that we are to speak within ourselves. Speak with prudence, so as to avoid falling into sin, as by excess of talking. When you sit in your house, speak to yourself as if you were a judge. When you walk along the way, speak so as to never be idle. You speak along the way if you speak in Christ, for Christ is the way. When you walk along the way, speak to yourself, speak to Christ. Hear him say to you: I desire that in every place men should pray, lifting holy hands without anger or quarreling. When you lie down, speak so that the sleep of death may not steal upon you. Listen and learn how you are to speak as you lie down; I will not give sleep to my eyes or slumber to my eyelids until I find a place for the Lord, a dwelling place for the God of Jacob.
When you get up or rise again, speak of Christ, so as to fulfill what you are commanded. Listen and learn how Christ is to awaken you from sleep. Your soul says: I hear my brother knocking at the door. Then Christ says to you: Open the door to me, my sister, my spouse. Listen and learn how you are to awaken Christ. Your soul says: I charge you, daughters of Jerusalem, awaken or reawaken the love of my heart. Christ is that love.