Many christians (small c intended to denote children) promoting "God is love" and "Love(God) another as I have loved you" fail to God(Love) one another as Jesus Christ did, without partiality and hypocrisy.
The area they seem to fail in most is realizing law is imperfect, and the exhortation is "be ye perfect", as perfect as your Father in heaven is perfect love, which hath no fear at all, and pure grace which hath no law at all, just as that God is light and in him there is no darkness at all, no sin at all.
Many such will sport bumper stickers saying Christians aren't perfect, they're just saved; while the Bible says Christians aren't just saved, they're perfected. Hence the exhortation to move on (from being babes unweaned from law) to perfection, which is the best part of good better best, and for all (not some only).
Perfection speaks of no law at all, not even mention of it, as in the conclusion of Hebrews and Revelation. For the law is notably imperfect, faulty, fault-finding, accusation-all (Jn 5:45), condemnation-all (2Cor 3), wrathful (Rom 4:15), vengeful, desiring sacrifical victims and a troll toll to cross a bridge over troubled water it did trouble in the first place. On the contrary God neither requested any sacrifice nor took any pleasure in sacrifice and offering which is "of the law" (Ps 40; Hos 6; Mt 9; Heb 10)... allegory: His Grace doesn't law anyone.
Clarity of "be ye perfect" in Mt 5:48 speaks of "be ye merciful" in Lk 6:36 (Luke notably having perfect understanding in Lk 1:3). Law is not merciful, but rather merciless; For in Hebrews it is notable all who died under Moses' law (law was given by Moses: Jn 1:17) died without mercy.
POINT: law can NEVER make comers thereunto perfect nor rid any of sin consciousness (Heb 10). For law is both the source (Rom 5:13) and the strength (1Cor 15:56) of sin, which brings forth death to all (Jam 1:15). So also law abiding does NOT make anyone righteous (Rom 9:31), but rather makes all unrighteous (Rom 3:10), sinners all (Rom 3;23).
POINT: be ye "perfect" speaks of pure grace void of law, perfect Love(God) void of fear, and of Love(God) one another "as I have loved you"... "the end of the commandment" notably being charity(love) out of a "pure" heart, which is the greatest of three things that are great greater greatest in 1Cor 13:13 http://www.godshew.org/GodShew.htm#Greatest
The "grace" of our Lord Jesus Christ with you all. Amen.