If we are to worship the Father, we first need to be reborn, becoming the Father's children (John 1:12; 1 John 3:1a).
In John 17:26a the Lord said that He would make the Father's name known to His disciples, and in Hebrews 2:12a we see that He declares the Father's name to His brothers. The name denotes the person. When you call on someone's name, the person comes, so the name of the Father denotes the Father's person. He is not only our God who created us but also the Father who begets us. He is not only the creating God but also the begetting Father. Now we are not only His creatures but also His children born of Him, begotten by Him. He is our Father, and we have to know His person. To know His person is to know His name.
All the disciples at that time had a Jewish background. They had the concept concerning God as their Creator, but they did not have any concept about God being their begetting Father. Before the Lord's resurrection, they did not have the concept that they were to be the children of God with God's life and nature. Before His resurrection, it was hard for the Lord to declare the Father's person to the disciples, because they did not have God as their Father. But in the resurrection He imparted the divine life into the disciples, so that made it easy for Him to make the Father's name, the Father's person, known to them.
On the day of His resurrection, He told Mary, "Go to My brothers and say to them, I ascend to My Father and your Father, and My God and your God" (John 20:17). The words brothers and your Father indicate an experience of life, a relationship in life. In His resurrection, the Lord imparted the Father's life and nature into the disciples. Now His Father is their Father and they are His brothers. This is all implied in knowing the Father's name, His person.
We worship the Father by enjoying the Father's presence. In John 14:23 the Lord said, "If anyone loves Me, he will keep My word, and My Father will love him, and We will come to him and make an abode with him." The Father and the Son will come to the one who loves the Son and will make Their abode with him. This is the constant presence of the Father. When we say, "Abba, Father" (Rom. 8:15; Gal. 4:6), we have a sweet inward sensation in an intimate enjoyment of the Father's presence.
By becoming the Father's children, by knowing the Father's name, and by enjoying the Father's presence, we worship the Father. If we are not born of the Father, do not know His person, and do not have His presence, we cannot worship Him subjectively. We can only worship an objective God.