5:5 and one of the elders said to me, "Stop weeping; behold, the Lion that is from the tribe of Judah, the Root of David, has overcome so as to open the book and its seven seals."

and one of the elders said to me,

This is IMPORTANT....it is not an angel talking to John but rather one of the elders, a redeemed one. Having been redeemed, the elder is able to admonish John to

"STOP WEEPING; BEHOLD the Lion that is from the tribe of Judah,

This is very ironic. The heaven was quieted by the question, "Who is worthy to open the seals?" And here we see John, who having been closest to the Christ in human form, crying as though there is no answer. This would indicate that while Christ was on earth, John just didn't really understand who Jesus was/is.

Or another viewpoint, John may just have realized why Christ came to earth, died, and was resurrected again. These may be tears of joy (and recognition). At any rate, the elder having been in heaven "longer" is the one to say to John, "It's OK, we have the Holy, Holy, Holy One in our midst to do the loosening."

The Lion is representative of STRENGTH. The Jews had always felt or wanted to believe that their Messiah would be strong and a leader (King). Jacob, when he gave his blessing to his sons, foretold that the Lion would come out of son Judah (Genesis 49:1,8-12). During the wanderings in the wilderness, it was the tribe of Judah that led the way (Numbers 10:13-14). Ultimately, in taking the promised land, the Lord promised to Judah that "He had given the land into Judah's hand" (Judges 1:1-2). That the Christ is the Lion (LEADER), he says himself that `all authority was given to HIM in heaven and on earth' (Matthew 28:18).

the Root of David

The Jews have long considered that David was the ultimate leader. Thus it is appropriate that the Root (creator) of David is identified here. Not only the Root but also the Offspring (Revelation 22:16) too.

HAS OVERCOME so as to open the BOOK and its seven seals."

This is the same "overcome" used with the seven churches in chapters 2 and 3. Since Christ is all-knowing, He knew that his assignment when he came to earth was to `overcome' by dying and by coming back to life again. He said as much in John 10:14-18.